Atomic Structures.

Question 1

What is an atom?

Answer 1

The smallest part of an element that can take part in a chemical change.

Question 2

Each atom is made up of subatomic particles. Name them.

Answer 2

Each atom is made of subatomic particles called protons, neutrons and electrons.

Question 3

What are protons?

Answer 3

A proton is a positively charged particle found in the nucleus of an atom.

Question 4

What is a neutron?

Answer 4

A neutron is a subatomic particle with no charge and is found in the nucleus of an atom.

Question 5

What is an electron?

Answer 5

An electron is a negatively charged particle found orbiting in the shell around a nucleus.

Question 6

What can collectively be called nucleons?

Answer 6

Protons and neutrons can collectively be called nucleons.

Question 7

Why is it correct to say that an atom is an electrically neutral entity?

Answer 7

An atom is an electrically neutral entity because they contain equal quantities of positively charged protons and negatively charged electrons.

Question 8

State the relative charge and approximate relative mass for a proton.

Answer 8

Relative charge of a proton = +1.
Approximate relative mass of a proton = 1.

Question 9

State the relativle charge and approximate relative mass for a neutron.

Answer 9

Relative charge of a neutron = 0 (neutral).
Approximate relative mass of a neutron = 1.

Question 10

State the relative charge and approximate relative mass for an electron.

Answer 10

Relative charge of an electron = -1.
Approximate relative mass of an electron = 1/1840.

Question 11

Define proton number (atomic number).

Answer 11

The proton number (or atomic number) is the number of protons in the nucleus of an atom.

Question 12

Define nucleon number (mass number).

Answer 12

Nucleon number (or mass number) is the total number of protons and neutrons in the nucleus of an atom.

Question 13

What is an element?

Answer 13

A substance containing only one type of atom and cannot be split into anything simpler.

For example sodium, chlorine, and argon.

Question 14

How are elements in the same periodic group similar?

Answer 14

Elements in the same periodic group have the same amount of electrons in their
outer shell, which gives them similar chemical properties.

Question 15

How are elements arranged in Periods?

Answer 15

Elements are arranged in order of increasing atomic number (proton number), in rows called
periods.

Question 16

Fill in the missing spaces :
The number of _____ or _____ _____ is the same as the period number.

Elements in the same Group have the same ______ of outer shell ________.

Answer 16

The number of shells or energy levels is the same as the period number.

Elements in the same Group have the same number of outer shell electrons.

Question 17

What is a compound?

Answer 17

A substance containing two or more types of atoms chemically combined.

For example sulfur dioxide, sulfuric acid, and magnesium oxide.

NOTE - The formation of a compound is irreversible.

Question 18

What is a mixture?

Answer 18

Two or more substances mixed together but not chemically combined.

Question 19

Define Isotopes.

Answer 19

Isotopes are atoms of the same element that contain the same number of protons and electrons but a different number of neutrons.

Question 20

What are the two types of isotopes?

Answer 20

Isotopes can be divided into two types: radioactive and non-radioactive.

Question 21

Give 1 MEDICAL uses of radioisotopes.

Answer 21

Medical :

• Medical instruments and materials are routinely sterilized by exposure to radiation.
• Radiation is extremely harmful and kills cells, radioisotopes are used to treat cancer.

Question 22

Give 1 INDUSTRIAL use of radioisotopes.

Answer 22

Industrial:
Radioactive tracers called a Geiger counter is deployed to detect leaks in gas or oil pipes.

Question 23

Why do isotopes have the same properties?

Answer 23

Isotopes have the same chemical properties because they have the same number of electrons in their outer shell and the number of electrons in the outer shell is responsible for chemical reactions and they also have the same number of protons so are still classed as the same element.

Question 24

Radioisotopes or radioactive isotopes are unstable, why?

Answer 24

Radioactive isotopes (radioisotopes) are unstable due to the imbalance of neutrons and protons, which causes the nucleus to decay over time.

Question 25

What are noble gases/group 8/ group 0 elements?

Answer 25

Nobles gases have 8 electrons in their outer shells already (except helium, which has 2), making them very stable and unreactive.

Question 26

How are electrons arranged?

Answer 26

Electrons are arranged around the nucleus in shells:
o First shell can have up to 2 electrons
o Second shell can have up to 8 electrons
o Third shell can have up to 8 electrons

Question 27

When reacting, why will all atoms try to acquire 8 electrons in the outer shell/the maximum number of electrons in the outer shell?

NOTE - Another name for the outer shell of an atom is the valence shell.

Answer 27

When reacting, all atoms try to acquire the maximum number of electrons in the outer shell because this is the most stable arrangement.