Question

29. Define an atom. An atom 'X' of an element has electronic configuration 2, 8, 2.
Write the following information about the element:
a) Atomic number of X
b) Valence electron
c) Valency
d) Is X' metal or non-metal
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Answer 1

Electronic configuration of 'X' is 2, 8, 8, 2. (a) X belongs to period 4 because it has 4 energy shells. (b) Since X has 2 valence electrons, so it belongs to group no.

Answer 2

Atom is a smallest part of a element .

An atom 'X' of an element whose EC is 2,8,2 is Magnesium ( Mg)

a) Atomic no. = 12

b) Valence electron = 2

c) valency = -2

d) X is metal .

Thank u !