Chapter 2~atomic Structure

Question 1

Chemical elements cannot be…

Answer 1

Broken down into simpler substances by chemical means

Question 2

Chemical elements only contain one type of?

Answer 2

Atom

Question 3

What is an atom?

Answer 3

An atom is the smallest part of an element that can take part in a chemical change. It is made up of sub-atomic particles namely: protons and neutrons which are in the nucleus; and electrons that orbit around the nucleus at different energy levels

Question 4

Definition of the nucleus

Answer 4

°the small dense core at the centre of every atom, containing nucleons so : protons (positively charged) and neutrons (no charge). Nuclei are therfore always positively charged

Question 5

Definition of a proton

Answer 5

°a positively charged subatomic particle situated in the the nucleus of an atom

Question 6

Definition of a neutron

Answer 6

°a subatomic particle situated in the nucleus of an atom. It has no charge and has the same mass as a proton

Question 7

Definition of an electron :

Answer 7

A tiny subatomic particle situated in orbitals / energy levels surrounding the nucleus. They have a negative charge and negligible mass

Question 8

Name the 2 types of nucleons :

Answer 8

1. Protons

2. Neutrons

Question 9

The e- in a cathode-ray tube is deflected by an electromagnetic field (has a positive and negative side). The direction of the deflection shows us the

Answer 9

Charge of the electrons (negative)

Question 10

Experiments with subatomic particles. Low voltages are needed to show the deflection of

Answer 10

Electrons

Question 11

Experiments with subatomic particles:

Huge voltages are use to show the deflection of

Answer 11

Protons

Question 12

Relative masses of electrons, protons and neutrons :

Answer 12

e-= 1/1836

p+= 1

n= 1

Question 13

Relative charge of electrons, neutrons and protons :

Answer 13

e-= - 1

p+= +1

n=0

Question 14

Definition of Nucleon number or mass number:

Answer 14

°the total number of of protons and neutrons in the nucleus of an atom

Question 15

Nucleon number =

Answer 15

= number of protons + number of neutrons

Question 16

In a neutral atom the number of protons =

Answer 16

The number of electrons

Question 17

Definition of an isotope :

Answer 17

Isotopes are atoms of the same element (therefore same proton number) with different nucleon (mass) numbers (because there is a different number of neutrons)

Question 18

Isotopes can fall under two types :

Answer 18

1. non - radioactive isotopes

2. Radioisotopes

Question 19

3 uses of radioisotopes :

Answer 19

1. Check for leaks in oil or gas pipelines using a Geiger meter
2. Check the thickness of paper
3. Used in medicine to treat some types of cancer and to check the activity of the thyroid gland in the throat

Question 20

Ions are formed when an atom…

Answer 20

Gains or loses electrons