Which element contains the largest number of neutrons per atom?

a. Copper - 64

b. Nickel - 59

c. Iron - 56

d. Manganese - 55

An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.

All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other.

Copper: (per atom)

Number of protons = 29

Number of electrons = 29

Number of neutrons = 35

Nickel: (per atom)

Number of protons = 28

Number of electrons = 28

Number of neutrons = 31

Iron: (per atom)

Number of protons = 26

Number of electrons = 26

Number of neutrons = 30

Manganese: (per atom)

Number of protons = 25

Number of electrons = 25

Number of neutrons = 30