Science Test Ph Wk. 8 2018 (9e)

Question 1

Define atom

Answer 1

The smallest unit of matter, they are composed of a nucleus, containing neutrons and protons, as well as electrons which orbit them in shells.

Question 2

Define Element

Answer 2

An element is one out of the 118 elements in the periodic system. Each element has a unique number of protons (1 - 118), the number of protons an atom has determines which element it is, and its atomic number.

Question 3

Define Proton

Answer 3

A subatomic particle which exists in the nucleus of an atom. Protons have a positive charge.

Question 4

Define Neutron

Answer 4

A subatomic particle which exists in the nucleus of an atom. Neutrons have a neutral charge.

Question 5

Define Electron

Answer 5

A subatomic particle which orbits an atom’s nucleus. Electrons have a negative charge.

Question 6

Define Nucleus

Answer 6

The core of an atom, comprised of Neutrons and Protons.

Question 7

Define Atomic mass

Answer 7

The weight of an atom in AMU (Atomic Mass Units), this is found by doing #protons + #neutrons.

Question 8

Define Atomic number

Answer 8

The number of protons an atom has. Determines what element it is.

Question 9

Define Radiation

Answer 9

The emission of energy as electromagnetic waves or moving subatomic particles.

Question 10

Define Decay

Answer 10

The process in which an unstable nucleus goes through either Alpha or Beta decay, and becomes another element.

Question 11

Define Isotope

Answer 11

A variation of an element, with a unique number of neutrons.

Question 12

Define Half-life

Answer 12

The time it takes for half of the remaining nuclei of a radioactive substance to decay.

Question 13

Define Ionization

Answer 13

The process adding or removing electrons or protons from an atom in order to make it either positively or negatively charged.

Question 14

Define Background-radiaiton

Answer 14

The uniform radiation constantly affecting us.

Question 15

Define Radon

Answer 15

One of the only commonly found radioactive gases, which sippers from the bedrock, and enter our homes.

Question 16

Define Radioisotope

Answer 16

An isotope with an unstable nucleus, causing it to be radioactive.

Question 17

Define Tracer

Answer 17

A chemical compound containing some radioisotopes, which can be tracked through chemical reactions by tracing the path that the radioisotope follows from the reactants to the products.

Question 18

Define Nuclear fission

Answer 18

The process of bombarding radioactive elements such as uranium with neutrons, to cause them to split, and shoot out 3 neutrons, causing other uranium atoms to split, causing a chain reaction which in turn generates an enormous amount of energy, which warms a coolant, which heats waters in pipes, that boil, turn into steam and turn a turbine which turns a generator which generates electricity.

Question 19

Define Nuclear fusion

Answer 19

The process of multiple atoms (usually with low atomic numbers) combine to create a single, more massive atom. This releases a large amount of energy, which can then be converted into electricity. An example of this, is hydrogen nuclei merging to form helium nuclei.

Question 20

Define Nuclear waste

Answer 20

Every 10 years, the radioactive element used to generate electricity through nuclear fission has been completely used up, and needs to be disposed of. The used up matter however, is still very radioactive, therefore the term NUCLEAR waste.

Question 21

What are the parts of an atom?
How many protons, neutrons and electrons do the following elements have?

1 H
1

42 Mo
96

17 Cl
35

Answer 21

Each atom is composed of a nucleus, containing protons 6 neutrons, and electrons orbiting this nucleus in shells.

1 H
1
Answer: 1 Proton, 1 Electron, 0 Neutrons

42 Mo
96
Answer: 42 Protons, 42 Electrons, 54 Neutrons

17 Cl
35
Answer: 17 Protons, 17 Electrons, 18 Neutrons

Question 22

What are the three types of radiation?

Answer 22

Alpha, Beta and Gamma

Question 23

What are some manmade and natural sources of background radiation?

Answer 23

Manmade: Hospitals, Former nuclear bomb tests, medicines

Natural: Sun, Cosmic rays, Radon gas, food

Question 24

What are some good uses of radiation?

Answer 24

Gamma treatment
Thickness control,
Checking welds, non-destructive testing

Question 25

For all 3 types of radiation:
What are their particles/waves?
How does it decay into another element?
How far can they travel?
What can stop them?
What are their charges?

Answer 25

Alpha Beta Gamma
2p+ 2n0 1e- Wave
-2 elements +1 element NaN
few cm few m millions of m
paper or air aluminum thick lead or water
+2 -1 0

Question 26

How does radioactive dating work?

Answer 26

It is used to determine the age of things.

Inorganic materials, such as rock contain Uranium-238 in then, and knowing the half-life of Uranium, and the ratio of Uranium to lead, which can help us determine the age of the rock.

This also works on organic dead things. Living things constantly take in some radioactive Carbon-14 in photosynthesis. When living things die, they stop taking in Carbon, and the C-14 slowly decays, with a half-life of 57000 years, from this we can date bones, wood, paper and cloth.

Question 27

How can (in detail) radiation be used in a positive way in modern day life.

Answer 27

1: Radioactive tracers.
This can be used in medicine. A patient is injected with a small amount of Iodine-123. Within 5 minutes, both kidneys should extract the iodine from the blod stream, and then within 20 minutes pass it with urine into the bladder. If this does not happen for one of the kidneys, which we can trace using a Geiger counter, we can know that one kidney is blocked.

2. Thickness control
   When creating paper, it is important that the paper is the right thickness. To do this, beta-radiation passes through paper to a Geiger counter, which makes sure that the correct amount passes through, otherwise, it alters the pressure of the rollers which roll out the paper.