Chapter 14

How do atoms absorb energy?

As its electrons move away from nucleous

J.J Thompson was the first to identify the?

Electron

All atoms of the same element have same number of what?

Electrons and protons

Where are electrons with higher energy located?

In outer shell away from nucleus

Atoms with the same atomic number but different atomic mass?

Isotopes

The number of protons and the number of neutrons in the nucleus of an atom is known as?

Mass number

Who developed the model that helped understand energy levels?

Neils Bohr

What is the charge of a complete atom?

Neutral

All atoms of the same element may have different number of?

Neutrons

The tiny core of an atom that contains most of the mass of the atom is the?

Nucleus

Atomic number is?

Number of protons

One type of particle that carries a positive charge?

Proton

A charged particle that accounts for nearly half the mass of an atom is the

Protons

What determines the mass of an atom?

Protons and neutrons

Atoms of the same element may contain the same number of

Protons but different number of neutrons

Nucleus of an atom that spontaneously breaks up to emit particles is called?

Radioactive

What do two negative charges do?

Repel eachother

Pick out the two diagrams that are the same element

Same # of protons, different # of neutrons

Strongest force in the universe?

Strong nuclear force

What hold together protons and neutron in the nucleus?

The strong nuclear force

When do atoms emit light?

When electrons move from higher level to lower level