Question

Write the symbol for each of the following ions:

Answer 1

Answer:

a) $_{31}^{71}\textrm {P^{3+}}$

b) $_{35}^{80}\textrm {Br^{-}}$

c) $_{90}^{232}\textrm {Th^{4+}}$

d) $_{38}^{87}\textrm {Sr^{2+}}$

Explanation:

For neutral atoms:

Atomic Number (Z)= number of protons = number of electrons

Mass number (A) = number of protons + number of neutrons

For ions with positive net charge:

Number of protons = Z + net charge

For ions with negative net charge:

Number of protons= Z - net charge

a) A = 71, Charge = +3

Number of electrons = 28

Number of protons = 28 +3 =31

$_{31}^{71}\textrm {P^{3+}}$

b)  A = 35, Z = 45+35=80, Charge = -1

Number of protons =35

Number of neutrons = 45

Number of electrons = 36

Charge = Number of protons- Number of electrons =35-36 = -1

$_{35}^{80}\textrm {Br^{-}}$

c)  Charge = +4

Number of electrons = 86

Number of protons = Z = 86+4 = 90

mass number = A = 90+142 = 232

$_{90}^{232}\textrm {Th^{4+}}$

d)  Charge = +2

Atomic number = Number of protons = Z = 38

mass number = A = 87

$_{38}^{87}\textrm {Sr^{2+}}$