S4 All Definitions

Question 1

Element

Answer 1

A pure substance that cannot be broken down into anything simpler by chemical methods.

Question 2

Compound

Answer 2

A pure substance that consists of two or more elements chemically joined together.

Question 3

Mixture

Answer 3

It is made up of two or more substances (elements or compounds) that are not chemically joined together.

Question 4

Solute, solvent, solution

Answer 4

Solute + solvent = solution

Question 5

Dilute solution

Answer 5

It contains a small amount of solute in a given volume of solution.

Question 6

Concentrated solution

Answer 6

It contains a large amount of solute in a given volume of solution.

Question 7

Saturated solution

Answer 7

It contains solute such that no more solute dissolved in the solution at the temperature.

Question 8

Filtrate

Answer 8

Substances that pass through the filter paper in filtration.

Question 9

Residue

Answer 9

Substances that are trapped on the filter paper in filtration.

Question 10

Distillate

Answer 10

Liquid product condensed from vapour in distillation.

Question 11

Physical change

Answer 11

A change in which no new substance is formed.

Question 12

Chemical change

Answer 12

A change in which at least one new substance is formed.

Question 13

Physical properties

Answer 13

Properties that can be observed or measured without changing the chemical composition of the substance.

Question 14

Chemical properties

Answer 14

Properties that can be observed or measured without changing the chemical composition of the substance only when the substance undergoes a chemical change to form new substances.

Question 15

Ores

Answer 15

Rocks containing minerals in concentrations that are high enough for economical extraction.

Question 16

Effervescence

Answer 16

Bubbling / fizzing

Question 17

Weathering

Answer 17

The process where rock is dissolved, worn away or broken down into smaller and smaller pieces.

Question 18

Erosion

Answer 18

The process of moving weathered rock materials to another place by ice, water, wind, or gravity.

Question 19

Atom

Answer 19

The smallest particle of an element that still has its chemical properties.

Question 20

Brittle

Answer 20

Appears hard on the surface but breaks easily.

Question 21

Malleable

Answer 21

Can be hammered into a shape

Question 22

Ductile

Answer 22

Can be drawn into a wire

Question 23

Metalloids

Answer 23

Elements that do not fit easily into metals or non-metals.

Question 24

Semi-conductor

Answer 24

Pure form does not conduct electricity, conductivity increases when impurity is added.

Question 25

Z

Answer 25

Atomic number

Question 26

Atomic number (Z)

Answer 26

Number of protons in an element.

Question 27

A

Answer 27

Mass number

Question 28

Mass number (A)

Answer 28

Sum of numbers of protons and neutrons of an atom.

Question 29

Isotopes

Answer 29

Difference atoms of an element which have the same number of protons but a different number of neutrons.

Question 30

Relative isotopic mass

Answer 30

Mass of an isotope of an element, relative to 1/12 the mass of a carbon-12 atom.

Question 31

Relative atomic mass

Answer 31

Weighted mean mass of an element taking in to account the relative abundance of isotopes in a naturally occurring sample of the element, relative to 1/12 the mass of a carbon-12 atom.

Question 32

Transition metals

Answer 32

Metals between group II and group III of the periodic table.

Question 33

Period number

Answer 33

Indicates the number of occupied electron shells on an atom of the element.

Question 34

Group number

Answer 34

Indicates the number of outermost shell electrons in an atom of the element.

Question 35

Alkali metals

Answer 35

Elements in group I

Question 36

Alkaline earth metals

Answer 36

Elements in group II

Question 37

Halogens

Answer 37

Elements in group VII

Question 38

Noble gases

Answer 38

Elements in group 0

Question 39

Chemically inert

Answer 39

Rarely react with other substances

Question 40

Monoatomic ion

Answer 40

Formed when one atom loses or gains one or more electrons.

Question 41

Cation

Answer 41

Positive ion

Question 42

Anion

Answer 42

Negative ion

Question 43

Cation (+)

Answer 43

Formed when an atom of a metal (/ hydrogen) loses one or more outermost shell electrons.

Question 44

Anion (-)

Answer 44

Formed when an atom of a non-metal gains one or more outermost shell electrons.

Question 45

Charge of monoatomic cation

Answer 45

Group number of the element

Question 46

Charge of monoatomic anion

Answer 46

8 - group number of the element

Question 47

Conductors

Answer 47

Substances which conduct electricity but are not chemically changed during electrical conduction.

Question 48

Electrolytes

Answer 48

Substances which conduct electricity in molten state or aqueous solution but not in solid state, and are decomposed during the conduction.

Question 49

Non-conductors

Answer 49

Substances that do not conduct electricity in solid, molten state, or aqueous solution.

Question 50

Ionic bond

Answer 50

The strong electrostatic forces of attraction between oppositely charged ions.

Question 51

Ionic bond formation

Answer 51

Electrons are transferred from one atom (a group of atoms) to another (or group of atoms).

Question 52

Oxoanion

Answer 52

Polyatomic anion with oxygen

Question 53

Polyatomic ions

Answer 53

Ione formed from a group of atoms

Question 54

Chemical formula

Answer 54

A way to represent a chemical substance by using symbols and numbers.

Question 55

Delocalised electrons

Answer 55

Outermost shell electrons of atoms of metals that become free and move randomly throughout the metal.

Question 56

Metallic bond

Answer 56

The strong electrostatic forces of attraction between positive metal ions and a "sea" of delocalised electrons.