Ch. 2.1 : Atoms, Ions and Compounds

Question 1

Define the term ‘isotope’

Answer 1

Different atomic forms of the same element with the same number of protons but a different number of neutrons.

Question 2

Define the terms anion and cation

Answer 2

Anion - a negative ion, which goes to the positive anode

Cation - a positive ion, which goes to the negative cathode

Question 3

What is the mass number and atomic number?

Answer 3

Atomic number - smaller number - number of protons ( and subsequently electrons )
Mass number - larger number - number of protons and neutrons

Question 4

Describe the relative sizes of all the parts of an atom.

Answer 4

The nucleus is tiny compared to the rest of the atom, and so there is a lot of empty space in between the atom and electron shells.
The protons and neutrons are roughly the same size, whereas the electrons are smaller.
An electron is about 1/2000th the mass of a proton. ( 1/1836)

Question 5

Describe the different charges in an atom.

Answer 5

Proton : positive
Electrons : negative
The charge of a proton is equal but opposite to the charge on an electron. The charges balance.
Neutron : neutral / no charge

Question 6

How do you work out how many electrons there are?

Answer 6

Same as the number of protons.

Question 7

How can the atomic number be described as the identity of an element?

Answer 7

Every atom of the same element has the same number of protons.

Different elements have atoms that have different numbers of protons.

Question 8

What letters are used to represent mass number and atomic number?

Answer 8

Mass number : A -> number of protons and neutrons

Atomic number : Z -> number of protons

Question 9

Why do isotopes react the same way?

Answer 9

Different isotopes of the same element have the same number of electrons. The number of neutrons has no effect on the reactions of an element. Therefore, different isotopes of an element therefore react in the same way.

Question 10

What differences can exist between isotopes?

Answer 10

Physical properties e.g. Higher mass isotopes will have a higher melting point, boiling point, and density - but the chemical reactions are the same.

Question 11

What is an ion?

Answer 11

A charged atom. The number of electrons is different from the number of protons.

Question 12

What are cations and anions?

Answer 12

Cation : positive ion. It has fewer electrons than protons.

Anion : negative ion. It has more electrons than protons.