Question

a) Why do elements in a group have similar chemical properties?
b) Define Electron affinity. How it varies in a group and period?

Answer 1

Answer:

(a) Explain why: (i) All the elements of a group have similar chemical properties. (ii) All the elements of a period have different chemical properties. (b) The atomic radii of three elements X, Y and Z of a period of the periodic table are 186 pm, 104 pm and 143 pm respectively. Giving a reason arrange these elements in the increasing order of atomic number in the period.

(a). (i) All the elements of a group have similar chemical properties because they have same number of valence electrons in their outemost shell. (ii) All the elements of a periodic have different chemical properties because they have different number of valence electron in their atoms. (b) Order of atomic number of elements X

Answer 2

Answer:

(a).

(i) All the elements of a group have similar chemical properties because they have same number of valence electrons in their outemost shell.

(ii) All the elements of a periodic have different chemical properties because they have different number of valence electron in their atoms.

(b) Order of atomic number of elements X<Z<Y. Because as the atomic number increases in a period from left to right, the size of atom goes on decreasing.

Explanation:

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