Help me out real quick..

Detail is given below.

Explanation:

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. For example if neutral atom has 6 protons than it must have 6 electrons. The sum of neutrons and protons is the mass number of an atom while the number of protons are number of electrons is the atomic number of an atom.

Now we will solve the problems:

Nitrogen:

atomic mass  = 15 amu

Atomic number = 7

Protons = 7

Electrons = 7

Neutrons = 8

Protons = 23

Neutrons = 29

Atomic mass = 23+29 = 52 amu

Electrons = 23

Atomic number = 23

The given element is vanadium.

Electrons = 30

Atomic mass = 64 amu

Protons = 30

Neutrons = (64-30 = 34)

Atomic number = 30

The given element is zinc.

Atomic mass = 99 amu

Atomic number = 43

Protons = 43

Electrons = 43

Neutrons = 99-43 = 56

The given element is technetium.

Lutetium:

Atomic mass = 176 amu

Atomic number = 71

Protons = 71

Electrons =71

Neutrons = 176-71 = 105

Atomic mass = 224 amu

Atomic number = 87

Protons = 87

Electrons = 87

Neutrons = 224-87 = 137

The given element is francium.

Atomic number = 101

Neutrons = 157

Protons = 101

Atomic mass = 101 + 157 = 258 amu

Electrons = 101

The given element is mendelevium.

Atomic mass = 155 amu

Atomic number = 64

Neutrons = 155-64 = 91

Protons = 64

Electrons = 64

The given element is gadolinium.

Atomic mass = 157 + 102 = 259 amu

Atomic number = 102

Neutrons = 157

Protons = 102

Electrons = 102

The given element is nobelium.

Atomic mass = 62 + 88= 150 amu

Atomic number = 62

Neutrons = 88

Protons = 62

Electrons = 62

The given element is samarium.

the answer is   c.) 1575 j.

explanation: