Question

An element M has atomic mass 19 and atomic number 9, its ion is represented by ?

Answer 1

THE VALENCY WILL BE ELECTRON REQUIRED TO MAKE ATOM STABLE. M' ELECTRONIC CONFIGURATION IS 2,7.THEREFORE          ION  M1- (M 1 MINUS)

Answer 2

Answer: The ion of element having atomic number 9 is $M-$

Explanation:

An ion is formed when electron gets added or removed from an element. When electron gets removed from the element, it results in the formation of positive ion known as cation and when electron gets added to an element, it results in the formation of negative ion known as anion.

Atomic number is defined as the number of electrons or number of protons present in an element.

Number of electrons in the given element M = 9

Electronic configuration for this element = $1s^22s^22p^5$

This element require 1 electron to attain stable noble gas configuration of neon. Thus, this element will easily accept 1 electron and will form anion having -1 charge.

Thus, the ion of element having atomic number 9 is $M^-$