Chapter 7 Lesson 2 Homework

Nuclear Decay

A process that occurs when an unstable atomic nucleus changes into another more stable nucleus by emitting radiation.

Ion

An atom that is no longer neutral because it has gained or lost electrons.

Radioactive atom

An atom that spontaneously emits radiation.

Two numbers used to identify an element

Atomic number and atomic mass number.

Be able to find these details by looking at the periodic table.

Atomic number, average atomic mass, number of protons, number of neutrons, and number of electrons.

Isotope

Atoms of the same element. Each one has a different number of neutrons.

Which two particles are responsible for the mass of an atom and which two particles are responsible for the charge of an atom?

Mass number is found by adding the number of protons and the number of neutrons. The charge of an atom is determined by the number of valence electrons and the number protons.

How do the masses of protons, neutrons, and electrons compare?

Protons and neutrons are equal in mass (sum = 1 amu). Electrons are much smaller.

Where are protons, neutrons, and electrons located in an atom?

Protons and neutrons are located in the nucleus of an atom. Electrons are located in orbitals of different energy levels.

Three parts to any atom

Protons, neutrons, and electrons.

Alpha Decay

The atomic number of an atom decreases by two when it releases an alpha particle.

Average atomic mass

The average mass of the element's isotopes, weighted according to the abundance of each isotope.

Atomic number

The number of protons in the atom of an element.

Mass number

The sum of the number of protons and neutrons in an atom.

Gamma Decay

This does not contain particles, it only contains energy. So, when a gamma ray is released, it does not change one element into another element.

Beta Decay

When a beta particle is released, the atomic number of an atom increases by one because it has gained a proton.