Physical Science Module 13

Front 1

How are the number of protons and electrons in an atom related?

Back 1

There are usually the same number of protons and electrons in an atom, making it neutral in charge. When an ion forms through the loss or gain of an electron, the number will be different, and the atom will have a net charge.

Front 2

How are the number of protons and neutrons in an atom related?

Back 2

There is no definite relationship between the number of protons and neutrons, although they tend to be close in number, especially in the lower atomic weight elements.

Front 3

How does the number of neutrons affect an atom?

Back 3

The number of neutrons in an atom, while it does not affect the charge, does affect how stable the nucleus is (radioactivity.)

Front 4

What is a neutron composed of?

Back 4

A neutron is made from a proton, an electron, and an antineutrino.

Front 5

What are protons made of?

Back 5

Protons are composed of 3 quarks, which are constantly exchanging tiny particles called gluons.

Front 6

How does the nucleus, which is composed of positive and neutral charges, stay together?

Back 6

The protons and neutrons in the nucleus are held together by the strong force, which is created by the constant exchange of very short-lived particles called pions.

Front 7

atomic number

Back 7

The number of protons in an atom. This determines the type of element that the atoms belong to.

Front 8

What does the number of electrons in an atom determine?

Back 8

The number of electrons in an atom determines its chemical behavior - what things it tends to interact with.

Front 9

atomic mass number

Back 9

The number of protons and neutrons in an atom.

Front 10

isotope

Back 10

atoms with the same number of protons (same element) but different number of neutrons.

Front 11

element

Back 11

A collection of atoms with the same number of protons (although not necessarily the same number of neutrons.)

Front 12

What does the weak force govern?

Back 12

The weak force governs radioactivity.

Front 13

radioactive isotope

Back 13

atom with an unstable nucleus.

Front 14

How many electrons fill each Bohr orbit?

Back 14

orbit 1 - 2
orbit 2 - 8
orbit 3 - 18
orbit 4 - 32
orbit 5 - 50

Front 15

beta decay

Back 15

In beta decay, a neutron gives off an electron (and antineutrino), leaving a proton behind in the nucleus. This does not change the atomic mass number, but does change the atomic number, making the atom a different element.

Front 16

alpha decay

Back 16

In alpha decay, the nucleus gives off 2 protons and 2 neutrons, yielding a different atomic number and atomic mass number.

Front 17

gamma decay

Back 17

Nucleus gives off a high energy photon. The atomic mass number remains the same, as does the atomic number.

Front 18

What will stop the penetration of the 3 radioactive decay particles/rays?

Back 18

Alpha particles are very weak, stopped by a piece of paper.
Beta particles are slightly stronger, stopped by a thin metal sheet.
Gamma rays are very powerful, requiring inches of lead to stop them.

Front 19

half-life

Back 19

The time it takes for half of a radioactive sample to decay.

Front 20

What 2 assumptions must be made in order to trust radioactive dating?

Back 20

1. That you know how much C-14 was in the sample to begin with.
2. That the half-lives of isotopes have remained constant over time.