Question

The atomic numbers and mass numbers of three different atoms are given. Which element is indicated for each one? Enter the chemical symbol, not the chemical name.

Answer 1

This is an incomplete question, here is a complete question.

The atomic numbers and mass numbers of three different atoms are given. Which element is indicated for each one? Enter the chemical symbol, not the chemical name.

(1) Mass number = 16

Atomic number = 8

Element symbol = ?

(2) Mass number = 35

Atomic number = 17

Element symbol = ?

(3) Mass number = 59

Atomic number = 27

Element symbol = ?

Answer :

(1) Element symbol = O

(2) Element symbol = Cl

(3) Element symbol = Co

Explanation :

The symbol of an element is determined by the isotopic representation of an atom.

The isotopic representation of an atom is: $_Z^A\textrm{X}$

where,

Z = Atomic number of the atom

A = Mass number of the atom

X = Symbol of the atom

As we know that atomic number identifies the symbol of an element.

For example : Atomic number 2 identify that the element is helium and the symbol is (He).

For part (1) :

Mass number = 16

Atomic number = 8

The isotopic representation of an atom is, $^{16}_{8}O$

Element symbol = O (oxygen)

For part (2) :

Mass number = 35

Atomic number = 17

The isotopic representation of an atom is, $^{35}_{17}Cl$

Element symbol = Cl (chlorine)

For part (3) :

Mass number = 59

Atomic number = 27

The isotopic representation of an atom is, $^{59}_{27}Co$

Element symbol = Co (cobalt)