How will you find the valency of chlorine sulphur and magnesium

Valency: • The combining capacity of the atom of an element with the atoms of other elements in order to acquire eight electrons in its outermost shell (or two electrons in the first shell) is known as valency. • Valency of metal is =Number of valence electrons. • Valency of non-metal is = 8 -Number of valence electrons. Valency of Chlorine ( Cl ) : • The atomic number of Chlorine is 17 and it is a non-metal. • The electronic configuration of Chlorine is ( 2 , 8 , 7 ). Thus, Chlorine has 7 valence electrons. • Since it is a non-metal, Valency = 8 - 7 = 1. Thus, the valency of Chlorine is 1. Valency of Magnesium ( Mg ) : • The atomic number of Magnesium is 12 and it is a metal. • The electronic configuration of Magnesium is ( 2 , 8 , 2 ). Thus, Magnesium has 2 valence electrons. • Since it is a metal, Valency = 2. Thus, the valency of Magnesium is 2. Valency of Sulphur ( S ) : • The atomic number of Sulphur is 16 and it is a non-metal. • The electronic configuration of Sulphur is ( 2 , 8 , 6 ). Thus, Sulphur has 6 valence electrons. • Since it is a non-metal, Valency = 8 - 6 = 2. Thus, the valency of Sulphur is 2. Thus,, the valency of Chlorine, Magnesium and Sulphur are 1, 2 abd 2 respectively.

• Since atom has 7 valence electrons it is easier for the atom to gain 1 electron to achieve an octet. Valency of atoms gaining 1 electron = 1 Therefore, Valency of chlorine = 1 (ii) Sulphur • Atomic number of Sulphur = 16 • Electronic configuration of sulphur is - 2, 8, 6 • Number of valence electrons = 6 • Since the atom has 6 valence electrons it is easier for it to gain 2 electrons to achieve an octet . Valency of atoms gaining 2 electrons = 2 Therefore, Valency of sulphur = 2 (iii) Magnesium • Atomic number of magnesium = 12 • Electronic configuration of magnesium is - 2, 8, 2 • Number of valence electrons = 2 • Since the atom has 2 valence electrons it is easier for it to lose 2 electrons to achieve an octet . Valency of atoms losing 2 electrons = 2 Therefore, Valency of magnesium = 2

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i) Chlorine atom has 7 electrons in its outermost shell. Its valency is 7. But it is easier for chlorine to gain one electron instead of losing seven electrons. Hence its valency is determined by subtracting seven electrons from the octet and this gives us a valency of one for chlorine. ii) Sulphur atom has 6 electrons in its outermost shell. But it is easier for sulphur to gain two electrons instead of losing 6 electrons. Hence its valency is determined by subtracting 6 electrons from the octet and this gives us a valency of sulphur is two. iii) Outermost orbit of Magnesium has 2 electrons, hence it has valency two.

If the number of electrons in the outermost shell of the atom of an element is less than or equal to 4, then the valency of the element is equal to the number of electrons in the outermost shell. On the other hand, if the number of electrons in the outermost shell of the atom of an element is greater than 4, then the valency of that element is determined by subtracting the number of electrons in the outermost shell from 8. The atomic number of chlorine, sulphur and magnesium are 17, 16 and 12 respectively. The distribution of electrons in chlorine is 2, 8, 7. The distribution of electrons in sulphur is 2, 8, 6. The distribution of electrons in magnesium is 2, 8, 2. Therefore, the number of electrons in the outer most shell of chlorine, sulphur, and magnesium atoms are 7, 6, and 2 respectively. Thus, the valency of chlorine = 8 −7 = 1 The valency of sulphur = 8 − 6 = 2 The valency of magnesium = 2

(i) Valency of chlorine. The atomic number of chlorine is 17. The chlorine atom has 17 electrons, so its electron configuration is `underset("2, 8, 7")("K L M")`. A chlorine atom has 7 electrons in its valence shell (M shell). A chlorine atom can accept 1 more electron to achieve the inert gas electron arrangement (of 8 valence electrons), so the valency of chlorine is 1 (ii) Valency of sulphur. The atomic number of sulphur is 16. The sulphur atom has 16 electrons, so its electron distribution is `underset("2, 8, 6")("K L M")`. A sulphur atom has 6 electrons in its valence shell (M shell). A sulphur atom can accept 2 more electrons to acheive the inert gas electron arrangement (of eight valence electrons), so the valency of sulphur is 2 (iii) Valency of magnesium. The atomic number of magnesium is 12. The magnesium atom has 12 electrons, so its electron configuration is `underset("2, 8, 2")("K L M")`. A magnesium atom has 2 electrons in its outermost shell (M shell). A magnesium atom can lose its 2 outermost electrons to achieve the inert gas electron configuration (of 8 valence electrons), so the valency of magnesium is 2.