1. PERIODIC TABLE

2. Periodic table
The periodic table is a tabular arrangement of the chemical elements, organized on the basis of their atomic numbers, electron configurations (electron shell model), and recurring chemical properties.
Elements are presented in order of increasing atomic number (the number of protons in the nucleus).
The standard form of the table consists of a grid of elements laid out in 18 columns and 7 rows, with a double row of elements below that.
The table can also be deconstructed into four rectangular blocks: the s-block to the left, the p-block to the right, the d-block in the middle, and the f-block below that.

4. Periodic table which is used in Europe

5. The history of the periodic table reflects over a century of growth in the understanding of chemical properties. The most important event was the publication of the first periodic table by Dmitri Mendeleev in 1869.

6. The table is a visual representation of the periodic law which states that certain properties of elements repeat periodically when arranged by atomic number. The table arranges elements into vertical columns (groups) and horizontal rows (periods) to display these commonalities.
All versions of the periodic table include only chemical elements, not mixtures, compounds, or subatomic particles. Each chemical element has a unique atomic number representing the number of protons in its nucleus.
In the standard periodic table, the elements are listed in order of increasing atomic number (the number of protons in the nucleus of an atom).

7. A new row (period) is started when a new electron shell has its first electron.
Columns (groups) are determined by the electron configuration of the atom. Elements with the same number of electrons in a particular subshell fall into the same columns (e.g. oxygen and selenium are in the same column because they both have four electrons in the outermost p-subshell

8. Groups
A group or family is a vertical column in the periodic table. Groups usually have more significant periodic trends than periods and blocks, explained below.
Elements in the same group tend to show patterns in atomic radius, ionization energy, and electronegativity.

9. Groups
From top to bottom in a group, the atomic radii of the elements increase.
Since there are more filled energy levels, valence electrons are found farther from the nucleus. From the top, each successive element has a lower ionization. Similarly, a group has a top to bottom decrease in electronegativity due to an increasing distance between valence electrons and the nucleus.

10. A period is a horizontal row in the periodic table.
Periods
A period is a horizontal row in the periodic table.
Elements in the same period show trends in atomic radius, ionization energy, electron affinity, and electronegativity. Moving left to right across a period, atomic radius usually decreases. This decrease in atomic radius also causes the ionization energy to increase when moving from left to right across a period. Electronegativity increases in the same manner as ionization energy. Electron affinity also shows a slight trend across a period. Metals (left side of a period) generally have a lower electron affinity than nonmetals (right side of a period), with the exception of the noble gases.

11. The Periodic Table and physical properties
In the Periodic Table elements are placed in order of increasing atomic number. Elements with the same number of valence electrons are placed vertically in the same group. The groups are numbered from 1 to 8 (or 0).
Some groups have their own name:
Group 1- alkali metals
Group 7- halogens
Group 8 or 0- noble gases

12. Elements with the same outer shell of valence electrons are placed horizontally in the same period. The transition elements are located between groups 2 and 3.

13. Atomic radius
The atomic radius is the distance from the nucleus to the outermost electron. Since the position of the outermost electron can never be known precisely, the atomic radius is usually defined as half the distance between the nuclei of two bonded atoms of the same element.
As group is descended the outermost electron is in a higher energy level, which is further from the nucleus, so the radius increases.

14. Across a period electrons are being added to the same energy level, but the number of protons in the nucleus increases. This attracts the energy level closer to the nucleus and the atomic radius decreases across a period.

15. Ionic radius
It is important to distinguish between positive ions (cations) and negative ions (anions). Both cations and anions increase in size down a group as the outer level gets further from the nucleus.
Cations contain fewer electrons than protons so electrostatic attraction between the nucleus and the outermost electron is greater and the ion is smaller because the number of electron shells has decreased by one. Across the period the ions contain the same number of electrons, but an increasing number of protons, so the ionic radius decreases.

16. Anions contain more electrons than protons, so more electrons than in the parent atom. Across a period the size decreases because the number of electrons remains the same but the number of protons increases.

17. Periodicity
Elements in the same group tend to have similar chemical and physical properties. There is a change in chemical and physical properties across a period. The repeating pattern of chemical and physical properties shown by the different periods is known as periodicity.
These periodic trends can clearly be seen in atomic radii, ionic radii, ionization energies, electronegativities and melting points.

18. The Periodical Table and chemical properties
Chemical properties of elements in the same group
Group 1- the alkali metals
Lithium, sodium, and potassium all contain one electron in their outer. They are all reactive metals and are stored under liquid paraffin to prevent them reacting with air. They react by losing their outer electron to form the metal ion. Because they can readily lose an electron they are good reducing agents. The reactivity increases down the group as the outer electron is in successively higher energy levels and less energy is required to remove it.

19. They are called alkali metal because they all react with water to from an alkali solution of the metal hydroxide and hydrogen gas. Lithium floats and reacts quietly, sodium melts into a ball which darts around on the surface, and the heat generated from the reaction with potassium ignites the hydrogen.
2Li(s) + 2H20(I) 2Li+(aq) + 20H-(aq) + H2(g)
2Na(s) + 2H20(I ) 2Na+(aq) + 20H-(aq) + H2(g)
2K(s) + 2H20(I) 2K+(aq) + 20H-(aq) + H2(g)

20. Group 7 - the halogens
The halogens react by gaining one more electron to form halide ions. They are good oxidizing agents. The reactivity decreases down the group as the outer shell is increasingly at higher energy levels and further from the nucleus. This, together with the fact that there are more electrons between the nucleus and the outer shell, decreases the attraction for an extra electron.

21. Cl2(aq) + 2Br-(aq) 2CI-(aq) + Br2(aq)
Chlorine is a stronger oxidizing agent than bromine, so can remove the electron from bromide ions in solution to form chloride ions and bromine. Similarly both chlorine and bromine can oxidize iodide ions to form iodine.
Cl2(aq) + 2Br-(aq) CI-(aq) + Br2(aq)
Cl2(aq) + 2I-(aq) CI-(aq) + I2(aq)
Br2(aq) + 2I-(aq) Br-(aq) + I2(aq)

22. Test for halide ions
The presence of halide ions in solution can be detected by adding silver nitrate solution. The silver ions react with the halide ions to form a precipitate of the silver halide. The silver halides can be distinguished by their colour. These silver halides react with light to form silver metal. This is the basis of photography.

23. Metalloid
A metalloid is a chemical element that has properties that are in between those of metals and nonmetals.
The six elements commonly recognised as metalloids are boron, aluminium, germanium, arsenic, antimony and tellurium. On a standard periodic table all of these elements can be found in or near a diagonal region of the p-block, having its main axis anchored by boron at one end and astatine at the other. Some periodic tables include a dividing line between metals and nonmetals and it is generally the elements adjacent to this line or, less often, one or more of the elements adjacent to those elements, which are identified as metalloids.

24. Physically, metalloids usually have a metallic appearance but they are brittle and only fair conductors of electricity; chemically, they mostly behave as (weak) nonmetals. They can form alloys with metals.

25. Here are the general physical properties exhibited by metalloids.
Metalloids are solids at room temperature.
They are lustrous i.e. they have
a shiny surface like metals.
Some of them are ductile in nature and
can be drawn into pipes and wires.
silicon

26. They are usually brittle in nature.
They are fair conductors of heat and electricity, but not as good as metals. Hence, they are also known as semi-conductors. Metalloids like boron, germanium, and arsenic are used as dopants in glasses for use in semiconductor chips.
They are usually brittle in nature.
These elements mostly exist in several allotropic forms.
The density of metalloids is lower than that of poor metals, but higher than that of non-metals.
germanium

27. The temperature coefficient of resistance can be positive (arsenic and antimony) or negative (boron, silicon, germanium, tellurium) for metalloids.
They have an open crystal structure, as opposed to the closed crystal structure of metals.
They have abnormally high values of enthalpy of fusion.
They exhibit electrical conductivity even in the liquid form.
In metalloids, fewer valence electrons are available as "free electrons".

28. Chemical Properties
Metalloids tend to have an intermediate property between metals and non-metals. Given below are some general chemical properties of metalloids.
In a standard periodic table layout, you will observe that the metalloids that are placed on the upper right side of the diagonal line through the p-block, display increasing non-metallic behavior. However, those placed to the lower left of the line are more metallic in character. This diagonal line is called the 'stair-step' or 'staircase'.
Arsenic

29. The general chemical behavior of metalloids is similar to that of non-metals.
Many metalloids have multiple of oxidation states or valences. However, in most chemical reactions, they may behave either as metals or non-metals.
The metalloids usually form amphoteric oxides. The oxides formed by metals are basic oxides, while non-metals generally form acidic oxides.
The ionization energy of metalloids is higher than that of metals, but lower than that of non-metals.

30. Many metalloids have different allotropes
Many metalloids have different allotropes. For a given metalloid, one of its allotrope may react as a metal and the other allotrope may behave as a non-metal. For example, carbon in its diamond allotrope acts like a true non-metal and is a bad conductor of electricity, but its graphite allotrope is a fairly good electrical conductor.
Allotropes of tin, phosphorous and bismuth exhibit borderline behavior.
Metalloids form anions (negatively charged ions) in water.

31. These elements can form ionic as well as covalent bonds.
The oxidation number for metalloids can be positive or negative.
Metalloids can react with metals to form alloys.
The oxides of metalloids are weakly acidic. They are amorphous and when heated beyond a certain temperature, which is known as the glass transition temperature), form glass.
tellurium

32. Transition Metal
The transition metals, also called the d-block elements, are found in groups 3-12 of the periodic table. These elements make the transition between the representative metals in groups 1 and 2 and the metalloids, representative metals, and nonmetals in groups Moreover, it is in this block of elements in the periodic table that the d-orbitals are being filled with electrons. For example, elements in the first group of the d-block (group 3 of the periodic table: scandium, yttrium, lanthanum, and actinium) each have one d-electron. Likewise, elements in the eighth group of the d-block (group 10 of the periodic table: nickel, palladium, and platinum) each have eight d-electrons when in the +2 oxidation state.

34. The transition metals have several features in common: unlike representative metals, most transition metals have variable valence, meaning that they have more than one possible oxidation—or valence—state. For example, platinum exists most commonly in the +2 and +4 oxidation states, but it can also be found in the +5 and +6 oxidation states.

35. Properties
Because they possess the properties of metals, the transition elements are also known as the transition metals. These elements are very hard, with high melting points and boiling points. Moving from left to right across the periodic table, the five d orbitals become more filled. The d electrons are loosely bound, which contributes to the high electrical conductivity and malleability of the transition elements. The transition elements have low ionization energies. They exhibit a wide range of oxidation states or positively charged forms.

36. Properties
The positive oxidation states allow transition elements to form many different ionic and partially ionic compounds. The formation of complexes causes the d orbitals to split into two energy sublevels, which enables many of the complexes to absorb specific frequencies of light. Thus, the complexes form characteristic colored solutions and compounds. Complication reactions sometimes enhance the relatively low solubility of some compounds.

37. The formation of coloured compounds Some common examples
The diagrams show aproximate colours for some common transition metal complex ions.
When white light passes through a solution of one of these ions, or is reflected off it, some colours in the light are absorbed. The colour you see is how your eye perceives what is left.

38. CHANGE FROM METALLIC TO NON-METALLIC NATURE OF THE ELEMENTS ACROSS PERIOD 3
Metals tend to be shiny and are good conductors of heat and electricity. Sodium, magnesium, and aluminium all conduct electricity well. Silicon is a semi-conductor and is called a metalloid as it possesses some of the properties of a metal and some of a non-metal. Phosphorus, sulfur, chlorine, and argon are non-metals and do not conduct electricity. Metals can also be distinguished from non-metals by their chemical properties. Metal oxides tend to be basic, whereas non-metal oxides tend to be acidic.

39. Sodium oxide and magnesium oxide are both basic and react with water to form hydroxides, e.g.
Na20(s) + H20(l) NaOH(aq)
MgO(s) + H20(l) Mg(OH)2

40. Cl2(aq) + H20(l) HCI(aq) + HCIO(aq)
Aluminium is a metal but its oxide is amphoteric, that is, it can be either basic or acidic depending on whether it is reacting with an acid or a base.
The remaining elements in period 3 have acidic oxides. For example, sulfur trioxide reacts with water to form sulfuric acid, and phosphorus pentoxide reacts with water to form phosphoric (V) acid.
S03(g) + H20(l) H2S04(aq)
P4O10(s) +6H20(I) 4H3P04(aq)
Chlorine itself reacts with water to some extent to form an acidic solution.
Cl2(aq) + H20(l) HCI(aq) + HCIO(aq)

41. Thank you for your attention !