Topic 2: Atoms, Elements and Compounds

Question 1

An atom

Answer 1

is the smallest part of an element that can exist as a stable entity

Question 2

An ion

Answer 2

is a species with a positive or negative charge

Question 3

An element

Answer 3

is a substance that is made of atoms with the same atomic number, or a substance that cannot be split up by chemical means

Question 4

A compound

Answer 4

is a pure substance, which contains two or more different elements, chemically bonded together

Question 5

A molecule

Answer 5

is the smallest part of an element or a compound, which can exist alone under ordinary conditions

Question 6

A mixture

Answer 6

is two or more substances that can be separated by physical means

Question 7

Proton (atomic) number

Answer 7

is equal to the number of protons in the nucleus of an
atom

Question 8

Mass (nucleon) number

Answer 8

is equal to the total number of protons and neutrons in the
nucleus of an atom

Question 9

Isotopes

Answer 9

are different atoms of the same element, with the same number of protons but different number of neutrons

Question 10

An ionic bond

Answer 10

is a strong electrostatic attraction between oppositely charged ions

Question 11

An ionic lattice

Answer 11

is a giant structure of ionic compounds with a regular arrangement of alternating positive and negative ions

Question 12

A covalent bond

Answer 12

is formed when a pair of electrons is shared between atoms leading to noble gas electronic configurations

Question 13

A macromolecule

Answer 13

consists of a large number of atoms bonded together to form one molecule with a very high relative molecular mass (Mr)

Question 14

Allotropes

Answer 14

are different crystalline forms of the same element. They have the same chemical properties, but different physical properties

Question 15

Metallic bonding

Answer 15

is an electrostatic attraction between the positive ions in a giant metallic lattice and a „sea‟ of delocalised electrons

Question 16

physical property

Answer 16

is something about the appearance or state of a material.

Question 17

chemical property

Answer 17

is something about the chemistry of a material.