Question

The atomic number of an element is 20. (a) Write its electronic configuration and determine its valency. (b) Is it a metal or a non-metal ? (c) Write the formula of its chloride. (d) Is it more reactive or less reactive than Mg (atomic number 12) ? Give reason for your answer.

Answer 1

a) Me20=1s2 2s2 2p6 3s2 3p6 4s2
or
Me20=2)8)8)2)
The valence electron is 2
b)It is metal- Ca

`c) \: {Ca}^( + 2) \: and \: {Cl}^( - 1) \\ form \: CaCl2 \: compound \\`


d) it is more reactive than Mg
Becayse,
Calcium electropositive than magnesium