Atoms

Question 1

What are atoms?

Answer 1

The smallest unit of a pure substance.
It makes up ‘matter’.

Question 2

What is the structure of atoms?

Answer 2

Sub-atomic particles: protons, neutrons, electrons and space

Question 3

What is the electrical charge, mass and position of the proton?

Answer 3

Positive charge, 1840x electron mass ( = neutron mass), inside nucleus

Question 4

What is the electrical charge, mass and position of the neutron?

Answer 4

No (neutral) charge, 1840x electron mass ( = proton mass), inside nucleus

Question 5

What is the electrical charge, mass and position of the electron?

Answer 5

Negative charge, 1x electron mass ( = neutron mass), shells

Question 6

What is the centre of an atom called and what sub-atomic particles are present?

Answer 6

Protons and neutrons make up the nucleus.

Question 7

Where is the mass of an atom concentrated and why?

Answer 7

In the nucleus because protons and neutrons have a heavier mass than electrons.

Question 8

What is the charge of an atom and why?

Answer 8

The overall charge of an atom is zero (electrically neutral) because there is a balance between positive and negative charges, meaning they have the same number of protons and electrons.

Question 9

What is most of an atom’s volume made up of?

Answer 9

Empty space.

Question 10

What is the overall charge of the nucleus?

Answer 10

Positive - protons have a positive charge and neutrons have no charge.

Question 11

What is an element?

Answer 11

Pure substance made of one kind of atom.

Question 12

What is a compound?

Answer 12

Chemically combined atoms of two or more elements.

Question 13

What is a mixture?

Answer 13

Two or more substances not chemically combined.

Question 14

Atomic number = ?

Answer 14

The number of protons.

Question 15

Different number of protons =

Answer 15

Different elements formed.

Question 16

Protons + neutrons = ?

Answer 16

Mass number

Question 17

Mass number - atomic number = ?

Answer 17

Number of neutrons

Question 18

Number of electrons = ?

Answer 18

Number of protons (atomic number)

Question 19

What is the notation of atoms?

Answer 19

Nuclear symbol form - atomic mass/weight, atomic number, atomic symbol.

Question 20

What are electrons arranged into and how many can go into each?

Answer 20

Shells or energy levels.
1st = 2
2nd = 8
3rd = 8

Question 21

Can electrons be lost or gained?

Answer 21

Yes, electrons on the valence (outer) shell can be transferred to another atom.

Question 22

What happens when electrons are lost or gained and what is the result of it?

Answer 22

There is an imbalance of positive and negative charges. This results in an overall positively or negatively charged particle.

Question 23

What is an ion and what is the name of the formation of ions?

Answer 23

An atom or particle with a net charge; charged atoms. The process is called ionisation.

Question 24

When does ionisation occur?

Answer 24

When atoms form chemical bonds or are exposed to radiation.

Question 25

Why do ions normally have a full outer shell of electrons?

Answer 25

It is a stable arrangement.

Question 26

What is the difference between metal and non-metal ions?

Answer 26

Metal ions lose electrons while non-metal ions gain electrons.

Question 27

What do the names of negative ions usually end with?

Answer 27

"ide". e.g. when oxygen becomes a negative ion its name changes to oxide.

Question 28

How is an ion written?

Answer 28

Element symbol followed by overall charge in subscript. e.g. if oxygen gains 2 electrons, it has a charge of -2. the name and formula of the ion is oxide (O^2-)

Question 29

Why can current flow through water?

Answer 29

Water contains ions of dissolved salts and metals which freely move throughout the fluid.

Question 30

Negative ions form when an atom _______ electrons and positive ions form when an atom ________ electrons.

Answer 30

gains, loses

Question 31

What is static electricity?

Answer 31

When you rub two objects together, there is a temporary transfer of electrons which causes an imbalance of electrical charges.

Question 32

What is the relationship between positive and negative charges?

Answer 32

Opposite charges attract, like charges repel.

Question 33

What are isotopes?

Answer 33

Isotopes of an element have the same number of protons but different number of neutrons, meaning it has a different mass number. They have the same chemical properties.

Question 34

Which one is more unstable: heavier or lighter isotopes?

Answer 34

Heavier isotopes tend to break down into smaller atoms because they are more unstable.

Question 35

True or False?: Most elements exist as a mixture of isotopes.

Answer 35

True

Question 36

For isotopes, mass number is __________ while atomic number is the _________

Answer 36

Different, same

Question 37

What is a molecule?

Answer 37

Two or more atoms connected by chemical bonds. The smallest division of a compound.

Question 38

What is a positive and negative ion called?

Answer 38

Cations and anions.

Question 39

Electron cloud model vs. planetary model

Answer 39

Model of an atom in which electrons move freely. Model of an atom in which electrons move in defined orbits.