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Periodic system of chemical elements D.I. Mendeleev

MENDELEEV Dmitry Ivanovich (1834-1907) an outstanding Russian figure in science and culture, author of fundamental research in chemistry, chemical technology, physics, metrology, aeronautics, meteorology, agriculture, economics, etc.

The history of the discovery of the table The pioneer of the table was the Russian scientist Dmitry Mendeleev. An extraordinary scientist with the broadest scientific horizons managed to combine all ideas about the nature of chemical elements into a single coherent concept. By the middle of the 19th century, 63 chemical elements had been discovered, and scientists all over the world repeatedly attempted to combine all the existing elements into a single concept. The elements were proposed to be placed in ascending order of atomic mass and divided into groups according to the similarity of chemical properties. In 1863, the chemist and musician John Alexander Newland proposed his theory, who proposed a layout of chemical elements similar to that discovered by Mendeleev, but the work of the scientist was not taken seriously by the scientific community due to the fact that the author was carried away by the search for harmony and the connection of music with chemistry. In 1869, Mendeleev published his scheme of the periodic table in the journal of the Russian Chemical Society and sent out a notice of the discovery to the leading scientists of the world. In the future, the chemist repeatedly refined and improved the scheme until it acquired its familiar form. The essence of Mendeleev's discovery is that with an increase in the atomic mass, the chemical properties of elements do not change monotonously, but periodically. After a certain number of elements with different properties, the properties begin to repeat. Thus, potassium is similar to sodium, fluorine is similar to chlorine, and gold is similar to silver and copper. In 1871, Mendeleev finally united the ideas into the Periodic Law. The scientist predicted the discovery of several new chemical elements and described their chemical properties. Subsequently, the chemist's calculations were fully confirmed - gallium, scandium and germanium fully corresponded to the properties that Mendeleev attributed to them.

The prototype of the scientific Periodic system of elements was the table "Experience of a system of elements based on their atomic weight and chemical similarity", compiled by Mendeleev on March 1, 1869. Over the next two years, the author improved this table, introduced ideas about groups, series and periods of elements; made an attempt to estimate the capacity of small and large periods, containing, in his opinion, 7 and 17 elements, respectively. In 1870 he called his system natural, and in 1871 - periodic. Even then, the structure of the Periodic Table of Elements acquired in many respects modern outlines. Extremely important for the evolution of the Periodic Table of Elements was the idea introduced by Mendeleev of the place of an element in the system; the position of the element is determined by the period and group numbers.

The periodic system of elements was developed by D. I. Mendeleev in 1869-1871.

The creation of the periodic system allowed D. I. Mendeleev to predict the existence of twelve elements unknown at that time: scandium (ekaboru), gallium (ekaaluminium), germanium (ekasilicium), technetium (ecamarganese), hafnium (an analogue of zirconium), polonium (ecateluru), astatine (ecaiodu), francium (ekacesium), radium (ekabarium), actinium (ekalanthanum), protactinium (ekatantalum). D. I. Mendeleev calculated the atomic weights of these elements and described the properties of scandium, gallium and germanium. Using only the position of the elements in the system, D. I. Mendeleev corrected the atomic weight of boron, uranium, titanium, cerium and indium.

Modern version of the periodic system of elements

A promising version of the system of elements

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1

Opening
Periodic Law
Based on their classification
chemical elements D.I. Mendeleev
put two of their main and permanent
sign:
atomic mass
properties formed by chemical
elements of matter.
2

Opening Periodic
law
In doing so, he discovered that the properties
elements within certain limits
change linearly (monotonically
increase or decrease), then after
jumps are repeated
periodically, i.e. through a certain
number of elements found similar.
3

First option
Periodic table
Based on their
observations March 1, 1869 D.I.
Mendeleev formulated
the periodic law, which
initial
the wording went like this:
properties of simple bodies, and
also forms and properties
connections of elements
are in periodic
depending on the quantities
atomic weights of elements
4

Periodic Law
DI. Mendeleev
If you write the rows one under the other like this,
so that sodium is under lithium, and under
neon - argon, we get the following
element arrangement:
Li Be B C N O
Na Mg Al Si P S
F Ne
Cl Ar
With this arrangement in vertical
columns
contain elements that are similar in their
properties.
5

Periodic law D.I. Mendeleev

Modern interpretation of the Periodic
law:
Properties of chemical elements
and the compounds they form
are in periodic
depending on the amount of charge
their atomic nuclei.
6

R
19
30,974
PHOSPHORUS
7

8

Periods

Periods - horizontal rows
chemical elements, only 7 periods.
Periods are divided into small (I, II, III) and
large (IV, V, VI), VII-unfinished.
9

Periods

Each period (except the first)
begins with a typical metal (Li, Na, K,
Rb, Cs, Fr) and ends with a noble
gas (He, Ne, Ar, Kr, Xe, Rn), which
preceded by a typical non-metal.
10

Groups

vertical columns
elements with the same
number of electrons per
external electronic
level equal to the number
groups.
11

Groups

There are main (A) and
side subgroups (B).
The main subgroups are
from elements small and large
periods.
Subgroups consist of
of only large elements
periods.
Such elements are called
transitional.
12

13

Remember!!!
Period number = number of energy
atom levels.
Group number = number of outer electrons
atom.
(For elements of main subgroups)
14

Valence

The group number indicates the highest
the valency of an element with respect to oxygen.
15

Valence

Elements IV, V, VI and VII of groups form
volatile hydrogen compounds.
Group number shows
the valence of an element in compounds with
hydrogen.
8-group no.
16

17

Exercise:

Name the period and
which group, subgroup
are the following
chemical elements:
Sodium, Copper, Carbon, Sulfur,
Chlorine, Chromium, Iron, Bromine
18

Changing the radius of an atom
in the period
The radius of an atom decreases with
an increase in the charges of the nuclei of atoms in a period.
19

Changing the radius of an atom
in the period
In one group with increasing
period numbers atomic radii
increase.
20

Change in the radii of atoms in the table D.I. Mendeleev

21

Exercise:

Compare the radii of the following
chemical elements:
Lithium, sodium, potassium
Boron, carbon, nitrogen
Oxygen, Sulfur, Selenium
Iodine, Chlorine, Fluorine
Chlorine, sulfur, phosphorus
22

Electronegativity
Electronegativity is
the ability of an atom to attract
electron density.
Electronegativity in a period
increases with increasing
charge of the nucleus of a chemical element, then
is from left to right.
23

Electronegativity in
group increases with
decrease in the number
electronic layers of an atom
(down up).
by the most
electronegative
the element is fluorine (F),
but least
electronegative -
francium (Fr).
24

RELATIVE ELECTRIC NEGATIVITY
ATOMS
H
2,1
Li
Be
With
N
O
0,98
1,5
AT
3,5
F
4,0
Na
mg
Al
Si
P
S
Cl
0,93
1,2
To
Ca
0,91
1,04
Rb
Sr
0,89
0,99
2,0
1,6
Ga
1,8
In
1,5
2,5
1,9
Ge
2,0
sn
1,7
3,07
2,2
As
2,1
Sb
1,8
2,6
Se
2,5
Those
2,1
3,0
Br
2,8
I
2,6
25

Exercise:

Compare the EOs of the following
chemical elements:
sodium and oxygen
Carbon and hydrogen
oxygen and fluorine
Boron and nitrogen
Iodine, fluorine
Chlorine, phosphorus
26

properties
Restorative properties of atoms the ability to lose electrons when

Oxidizing properties of atoms the ability to accept electrons at
the formation of a chemical bond.
27

redox
properties
In the main subgroups from bottom to top, in
periods - from left to right
oxidizing properties of simple
substances of elements increase, and
restorative properties,
respectively, decrease.
28

Change properties
chemical elements
Oxidative and non-metallic
properties
Oxidizing and non-metallic properties
29

METALOIDS

B
Ge
Sb
Po
30

METALOIDS

According to their chemical properties
semimetals are nonmetals,
but according to the type of conductivity they belong to
conductors.
31

32

Thank you for your attention!!

33

STRUCTURE OF THE ATOM

34

STRUCTURE OF THE ATOM

1911 English scientist Ernest Rutherford
proposed a planetary model of the atom
35

Structure
atom
1. At the center of the atom is
positively charged
core.
2. All positive charge
and almost the entire mass of the atom
concentrated in its core.
Particle
3. The nuclei of atoms consist of
protons and neutrons
(nucleons).
4. Around the nucleus in closed
orbits revolve
electrons.
Charge Bulk
number
Electron
e–
-1
0
Proton
p+
+1
1
Neutron
n0
0
1
36

37

The structure of the atom

electron
proton
neutron
38

A chemical element is a type
atoms with the same charge
kernels.
Ordinal
room
element
in PS
=
Charge
nuclei
Number
Number
= protons = electrons
in the core
ē
Core charge
ordinal
number →
12
mg
Number of protons
Number of electrons
Z = +12
p+ = 12
ē = 12
39

Number of neutrons

In the atoms of one chemical
element number
p+ protons are always the same
(equal to the charge of the nucleus Z), and the number
neutrons N is different.
40

Number of neutrons
Number
protons Z
+
Number
neutrons N
=
Mass
number A
Number of neutrons N = A -Z
Mass number -
24
serial number -
12
mg
N = 24 - 12 = 12
41

Sample tasks

Determine for the proposed ChE:
serial number
mass number
nuclear charge
number of protons
number of electrons
number of neutrons
42

Isotopes are atoms of an element that have one
and the same nuclear charge, but different masses.
e–
-
e
–
e–
-
-
p+
n
+n
R
+
R
isotopes
hydrogen
n
Hydrogen
Deuterium
Tritium
1H
2D
3T
Number
protons (Z)
the same
1
1
1
Number
neutrons N
Other
0
1
2
Mass
number A
Other
1
2
3
43

Isotopes of chlorine
35
17
Cl
75%
37
17
Cl
25%
Ar = 0.75 * 35 + 0.25 * 37 = 35.5

The electronic shell is the totality of all
electrons in an atom
surrounding the core.
45

Electronic shell

An electron in an atom is bound
state with a nucleus and has energy,
which determines the energy level
on which the electron is located.
46

Electronic shell

An electron cannot have such
energy to be between
energy levels.
aluminum atom
carbon atom
Atom
hydrogen
47

Stationary and excited state of the atom

48

1
E1< E2 < E3
2
core
3
Energy levels n
(Electronic layers) - set
electrons with similar values
energy
Number of energy levels in an atom
equal to the number of the period in which
ChE is located in the PSCE.
49

Determine

Number
energy
levels for
H, Li, Na, K, Cu
50

Level distribution of electrons

N=2n2
formula
for
calculations
maximum number of electrons per
energy levels, where n is the level number.
1st level - 2 electrons.
2nd level - 8 electrons.
3rd level - 18 electrons.
51

The maximum number of electrons in 1 level

Level 1: 2ē
52

Maximum amount
electrons at levels 1 and 2
Level 1: 2ē
Level 2: 8ē
53

Maximum number of electrons at levels 1,2,3

1 level-2
2 level-8
3 level-18
54

Diagram of the electronic structure

Serial number
nuclear charge +6, total number ē - 6,
Carbon 6C is in the second period
two energy levels (in the scheme
depicted in brackets, under them write a number
electrons at a given energy level):
C +6))
6
2
4
55

Draw an electronic structure diagram for:

Li, Na
Be, O, P,
F, BR
56

energy levels,
containing the maximum number
electrons are called
completed.
They have an increased
resilience and stability
energy levels,
containing fewer
electrons are called
unfinished
57

4
BERYLLIUM
2
2
9,0122
outer energy level

Periodic table of chemical elements

Number of energy
atom levels.
= period number
Number of outer electrons = group no.
59

11
Na
22,99
sodium
60

outer electrons

Number of outer electrons = group no.
Electron
external
level
61

The structure of energy levels

Every energy level
consists of sublevels: s, p, d, f.
The sublevel consists of orbitals.
Electron Orbital - Region
most likely
the location of the electron in
space

Electronic orbital

S-sublevel electrons when moving around the nucleus
form a spherical electron cloud
Border
sublevels
S - cloud
63

The p-sublevel electrons form three
electronic clouds in the form of volumetric
eights
p - clouds
64

The shape of the p-sublevel orbitals

65

The shape of the orbitals d - sublevel

d - clouds
66

The shape of the orbitals f - sublevel

67

p
- electron orbital,
-electrons,
-storey location
denotes levels and sublevels
electrons.
The diagram shows
structure of the 1st and 2nd
electronic levels
oxygen atom
68

Electronic graphic formulas
Electronic graphic
formulas
The sublevel consists of orbitals E
n=4 - 4 sublevels (S, p, d, f)
n=4
S
n=3
S
n=2
S
n=1S
d
p
p
d
f
n=3 - 3 sublevels (S, p, d)
n=2 - 2 sublevels (S, p)
p
n=1 – 1 sublevel (S)
where n is the level number
69

quantum numbers

The state of each electron in an atom
usually described with four
quantum numbers:
main (n),
orbital (l),
magnetic (m) and
spin (s).
The first three characterize the movement
electron in space, and the fourth around its own axis.
70

quantum numbers

- energy parameters,
determining the state of the electron
and the type of atomic orbital in which
he is in.
1. Principal quantum number n
determines the total energy of the electron
and the degree of its removal from the nucleus
(energy level number);
n = 1, 2, 3, . . .
71

quantum numbers

2. Orbital (side)
the quantum number l determines the shape
atomic orbital.
Values ​​from 0 to n-1 (l = 0, 1, 2, 3,..., n-1).
Each value of l corresponds to
special orbital.
l = 0 - s-orbital,
l \u003d 1 - p-orbital,
l \u003d 2 - d-orbital,
l = 3 - f-orbital
72

3. Magnetic quantum number m

- determines the orientation of the orbital in
space relative to the outer
magnetic or electric field.
m = 2 l +1
Values ​​range from +l to -l, including 0.
For example, for l = 1, the number m takes
3 values: +1, 0, -1 so there are
3 types of p-AO: px, py, pz.
73

quantum numbers

4. The spin quantum number s can
take on only two possible values
+1/2 and -1/2.
They correspond to two possible and
opposite directions
own magnetic moment
an electron called a spin.


74

Electron properties
Spin characterizes its own
the magnetic moment of the electron.
To denote electrons with different
symbols are used for spins: and ↓ .

Pauli principle.
Hund's rule.
The principle of sustainability
Klechkovsky.
76

1) Pauli Ban
One AO ​​can have no more than two
electron, which must have different
back.
Allowed
Forbidden!
An atom cannot have two electrons with
the same set of all four
quantum numbers.
77

Planetary model of the beryllium atom

4
BERYLLIUM
2
2
1s
9,0122
2s

Planetary model of the beryllium atom

4
BERYLLIUM
2
2
1s
9,0122
2s
2p

Filling atomic orbitals with electrons

2) Hund's principle:
Steady state of the atom
corresponds to such a distribution
electrons within
energy sublevel,
which absolute value
the total spin of the atom
maximum
Allowed
Forbidden!
80

Rules for filling energy levels

Hund's rule
If, for example, three
p-cells of the nitrogen atom
distribute three electrons, then they
will be located each in
a separate cell, i.e. be placed
on three different
p-orbitals:
in this case, the total spin
is +3/2 because its projection
is equal to
These three electrons cannot
be located
thus,
because then the projection
total spin
ms = +1/2-1/2+1/2=+1/2 .
ms = +1/2+1/2+1/2=+3/2 .
Forbidden!
Allowed
81

Filling atomic orbitals with electrons

3) The principle of sustainability
Klechkovsky.
AO are filled with electrons in
order of increasing their energy
energy levels.
1s<2s<2p<3s<3p<4s<3d<4p<5s<4d
82

Klechkovsky's principle of stability.

First of all, fill in
orbitals whose min sum is (n+l).
If the sums are equal (n+l), the ones y
which n is less
1s< 2s < 2p < 3s < 3p < 4s < 3d ...
4s (4+0=4)
1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d
83

ELECTRONIC FORMULA
ATOM
Using electronic formulas
(configurations) can be shown
distribution of electrons over
energy levels and sublevels:
1s<2s<2p<3s<3p<4s<3d<4p<5s<4d
1s2 2s22p6 3s23p6 3d0 4s2
84

ELECTRONIC FORMULA
Example: Carbon, #6, period II,
IV group.
Scheme of electronic
atomic structure
С+6))
2 4
Electronic formula: 1s2 2s22p2
85

Algorithm for compiling electronic formulas.

Write down the sign of the chemical element and
the charge of the nucleus of its atom (element number).
Determine the amount of energy
levels (period number) and the number
electrons at each level.
We make an electronic formula,
taking into account the level number, the type of orbital, and
the number of electrons on it (principle
Klechkovsky).
86 the structure of atoms
Li
Na
To
Rb
O
S
Se
Te
90

91

findings

The structure of external
energy levels
repeated periodically,
therefore periodically
repeat and properties
chemical elements.
92

States of atoms
Atoms are stable only in some
stationary states, which
correspond to certain values ​​of energy.
The lowest of the permitted energy
states of an atom is called the ground state, and all
the rest are excited.
Excited states of atoms are formed
from the ground state during the transition of one
or several electrons from busy
orbitals into free (or occupied only
93
1 electron)

The structure of the manganese atom:

Mn
+25
2
8
13
2
d - element
1s22s22p63s23p64s23d54p0
ground state of an atom
excited state of an atom
94

The value of transition metals for the body and life.

Without transition metals our body
cannot exist.
Iron is the active principle
hemoglobin.
Zinc is involved in the production of insulin.
Cobalt is the center of vitamin B-12.
Copper, manganese and molybdenum, as well as
some other metals are included in
composition of enzymes.
95

ions

Ion - positive or negative
a charged particle produced by
donation or attachment by an atom or
a group of atoms of one or more
electrons
Cation - (+) charged particle, Kat
Anion - (-) charged particle, An
96

4. Comparison of metal
(non-metallic) properties with neighboring
period and subgroup elements.
5. Electronegativity, i.e. force
attraction of electrons to the nucleus.
101

Thank you for your attention!

102

Internet resources used:

smoligra.ru
newpictures.club/s-p-d-f-orbitals
infourok.ru
Interesting videos
https://www.youtube.com/watch?v=3GbGjc-kSRw
103

Find matching elements and their features:

ELEMENT
SIGN
A. Lithium
B. Fluorine
B. Nitrogen
D. Beryllium.
1) s-element
2) Non-metal
3) number of protons 9
4) f-element
5) number of electrons 4
6) d-element
7) Metal
8) Highest EC by
compared to the rest
variants of atoms
104

The periodic system of chemical elements was discovered by the great Russian scientist Dmitri Mendeleev in March 1869 and finally formulated in years.

MENDELEEV, Dmitry Ivanovich January 27 (February 8), 1834 - January 20 (February 2), 1907 Russian chemist Dmitry Ivanovich Mendeleev was born in Tobolsk in the family of the director of the gymnasium. Dmitry was the last, seventeenth child in the family. Of the seventeen children, eight died in infancy. While studying at the gymnasium, Mendeleev had very mediocre grades, especially in Latin.

In 1850 he entered the Department of Natural Sciences of the Faculty of Physics and Mathematics of the Main Pedagogical Institute in St. Petersburg. In 1850 he entered the Department of Natural Sciences of the Faculty of Physics and Mathematics of the Main Pedagogical Institute in St. Petersburg. In 1855, Mendeleev graduated from the institute with a gold medal and was appointed senior teacher at a gymnasium in Simferopol, but because of the outbreak of the Crimean War, he transferred to Odessa, where he worked as a teacher at the Richelieu Lyceum. In the years Mendeleev was on a scientific mission in Germany. In the years Mendeleev was on a scientific mission in Germany.

Returning, Mendeleev wrote "Organic Chemistry" - the first Russian textbook on this discipline, which was awarded the Demidov Prize. One of the important discoveries of Mendeleev belongs to this period - the definition of the "absolute boiling point of liquids", now known as the critical temperature. Wrote the classic work "Fundamentals of Chemistry". In the preface to the second edition of the first part of the textbook, Mendeleev cited a table of elements entitled "Experience in a system of elements based on their atomic weight and chemical similarity"

In 1860, Mendeleev, along with other Russian chemists, took part in the work of the International Congress of Chemists, at which S. Cannizzaro presented his interpretation of the molecular theory of A. Avogadro. This speech and discussion about the distinction between the concepts of atom, molecule and equivalent served as an important prerequisite for the discovery of the periodic law. In 1869, Mendeleev published his scheme of the periodic table in the journal of the Russian Chemical Society and sent out a notice of the discovery to the leading scientists of the world. In the future, the chemist repeatedly refined and improved the scheme until it acquired its familiar form. The essence of Mendeleev's discovery is that with an increase in the atomic mass, the chemical properties of elements do not change monotonously, but periodically.

One of the legends says that Mendeleev discovered the table of chemical elements in his sleep. However, Mendeleev only laughed at the critics. “I’ve been thinking about it for maybe twenty years, and you say: I sat and suddenly ... it’s ready!”, the scientist once said about his discovery.

Another legend credits Mendeleev with the discovery of vodka. In 1865, the great scientist defended his dissertation on the topic "Discourse on the combination of alcohol with water", and this immediately gave rise to a new legend. The contemporaries of the chemist laughed, saying that the scientist "does well under the influence of alcohol combined with water," and the next generations already called Mendeleev the discoverer of vodka.

Also, contemporaries teased Mendeleev's passion for suitcases. The scientist at the time of his involuntary inaction in Simferopol was forced to pass the time weaving suitcases. In the future, he independently made cardboard containers for the needs of the laboratory. Despite the clearly "amateur" nature of this hobby, Mendeleev was often called a "suitcase master."

Mandatory minimum knowledge

in preparation for the OGE in chemistry

Periodic system DI. Mendeleev and the structure of the atom

chemistry teacher

Branch of the municipal educational institution of the village of Poima

Belinsky district of the Penza region in the village of Chernyshevo

• Repeat the main theoretical issues of the 8th grade program;
• To consolidate knowledge about the causes of changes in the properties of chemical elements based on the provisions in the PSCE D.I. Mendeleev;
• To teach to reasonably explain and compare the properties of the elements, as well as the simple and complex substances formed by them according to the position in the PSCE;
• Prepare for the successful passing of the OGE in chemistry

Serial number chemical element

shows the number of protons in the nucleus of an atom

(nuclear charge Z) of an atom of this element.

12 r +

mg 12

MAGNESIUM

This is

his physical meaning

12 e -

Number of electrons in an atom

equal to the number of protons,

because the atom

electrically neutral

Let's fix it!

Sa 20

CALCIUM

20 r +

20th -

32 r +

32nd -

SULFUR

Let's fix it!

Zn 30

ZINC

30 r +

30th -

35 r +

35th -

BROMINE

Horizontal rows of chemical elements - periods

small

large

unfinished

Vertical columns of chemical elements - groups

main

side effects

An example of writing a diagram of the structure of an atom of a chemical element

Number of electron layers

in the electron shell of an atom is equal to the number of the period in which the element is located

Relative atomic mass

(rounded to the nearest whole number)

written in the upper left corner above

serial number

11 Na

Nuclear charge (Z) of sodium

Sodium: serial number 11

(written in the bottom left corner)

next to the symbol of a chemical element)

2∙ 1 2

2∙ 2 2

11th -

11r +

The number of neutrons is calculated

according to the formula: N(n 0 ) = A r – N(p + )

12n 0

Number electrons in the outer level for elements of main subgroups equal to group number , in which the element is located

Maximum number of electrons

at the level calculated by the formula:

2n 2

Let's fix it!

13 Al

The charge of the nucleus of an atom (Z) of aluminum

2∙ 1 2

2∙ 2 2

13th -

13r +

14n 0

Let's fix it!

9 F

Nuclear charge (Z) of fluorine

2∙ 1 2

9r +

9e -

10n 0

Within one period

1. Increasing:

I II III IV V VI VII VIII

Li Be B C N O F Ne

+3 +4 +5 +6 +7 +8 +9 +10

2 1 2 2 2 3 2 4 2 5 2 6 2 7 2 8

• The charge of the atomic nucleus
• The number of electrons in the outer layer of atoms
• The highest oxidation state of elements in compounds

Li +1 Be +2 B +3 C +4 N +5

• Electronegativity
• Oxidizing properties
• Non-metallic properties of simple substances
• Acid properties of higher oxides and hydroxides

Within one period

2. Decrease:

I II III IV V VI VII VIII

Li Be B C N O F Ne

+3 +4 +5 +6 +7 +8 +9 +10

2 1 2 2 2 3 2 4 2 5 2 6 2 7 2 8

• Atom radius
• Metallic properties of simple substances
• Restorative properties:

Li - only reducing agent , C - and oxidizing agent , and reducing agent ,

F - only oxidizing agent

• The main properties of higher oxides and hydroxides:

LiOH- base ,Be(OH) 2 – amphoteric hydroxide,

HNO 3 - acid

Within one period

3. Doesn't change:

I II III IV V VI VII VIII

Li Be B C N O F Ne

+3 +4 +5 +6 +7 +8 +9 +10

2 1 2 2 2 3 2 4 2 5 2 6 2 7 2 8

Number of electron layers

(energy levels)

in the atom

equals period number

Let's fix it!

In periods

left right

charge of the nucleus of an atom

• is increasing
• Decreases
• Doesn't change

Let's fix it!

In periods

on right left

number of energy levels

• is increasing
• Decreases
• Doesn't change
• First increases and then decreases

Let's fix it!

In periods

left right

restorative properties of the element

• Are getting stronger
• Weaken
• Do not change
• Weaken first, then intensify

Let's fix it!

Atoms of chemical elements

aluminum and silicon

have the same:

• Number of electronic layers;
• Number of electrons

Let's fix it!

Atoms of chemical elements

sulfur and chlorine

have different:

• The value of the charges of the nuclei of atoms;
• The number of electrons on the outer layer;
• Number of electronic layers;
• Total number of electrons

Within the same A group

1. Increasing:

• The charge of the atomic nucleus
• Number of electron layers in an atom
• Atom radius
• Restorative properties
• metal properties

simple substances

• Basic properties of higher oxides and hydroxides
• Acid properties (degree of dissociation) of oxygen-free acids non-metals

2 8 18 8 1

Within the same A group

2. Decrease:

• Electronegativity;

• Oxidizing properties;

• non-metallic properties

simple substances;

• Strength (stability) of volatile hydrogen compounds.

2 8 18 7

2 8 18 18 7

Within the same A group

3. Do not change:

• Number of electrons in external electronic layer

• Oxidation state elements in higher oxides and hydroxides (usually equal to the group number)

• Be +2 mg +2 Ca +2 Sr +2

2 2

2 8 2

2 8 8 2

2 8 18 8 2

Let's fix it!

• In the main subgroups

from below up

charge of the nucleus of an atom

• is increasing
• Decreases
• Doesn't change
• First increases and then decreases

Let's fix it!

In the main subgroups

from below up

number of electrons in the outer level

• is increasing
• Decreases
• Doesn't change
• First increases and then decreases

Let's fix it!

In the main subgroups

down up

oxidative element properties

• Are getting stronger
• Weaken
• Doesn't change
• First increases and then decreases

Let's fix it!

Atoms of chemical elements

carbon and silicon

have the same:

• The value of the charges of the nuclei of atoms;
• The number of electrons on the outer layer;
• Number of electronic layers;
• Total number of electrons in an atom

Let's fix it!

Atoms of chemical elements

nitrogen and phosphorus

have different:

• The value of the charges of the nuclei of atoms;
• The number of electrons on the outer layer;
• Number of electronic layers;
• Total number of electrons

• § 36, test pp. 268-272

• Table D.I. Mendeleev http://s00.yaplakal.com/pics/pics_original/7/7/0/2275077.gif
• Gabrielyan O.S. "Chemistry. Grade 9 "- DROFA, M., - 2013, p. 267-268
• Saveliev A.E. Basic concepts and laws of chemistry. Chemical reactions. 8 - 9 grades. - M .: DROFA, 2008, - p. 6-48.
• Ryabov M.A., Nevskaya E.Yu. "Tests in chemistry" to the textbook by O.S. Gabrielyan "Chemistry. Grade 9". – M.: EXAM, 2010, p. 5-7