Question

Q7. An element X contains 3 electrons as valence electrons and M shells valence shell.
a.What is the atomic number of X?
b. What is its valency?
C. Identify X as a metal or a non-metal.​

Answer 1

Answer:

a. 13

b. 3

c. metal

Explanation:

it's aluminum

Answer 2

Element X is Aluminium, $Al$.

• Since X contains 3 valence electrons and M as valence shell,
• Total number of electrons present in X will be $1s^{2}2s^{2}2p^{6}3s^{2}3p^{1}=2+2+6+2+1$
• Number of electrons $=13e^{-}$
• So, number of valence electrons of X will be 3 which is the valency of X.
• This is because excess of electrons present in valence shell is 3.

a. So, atomic number of X is 13.

b. Valency of X is 3.

c. X is a metal. X is Aluminium$(Al)$.