Elements, Compounds and mixtures

Question 1

What can you say about all the atoms in an element?

Answer 1

All the atoms in an element are the same.

Question 2

Are the atoms in different elements the same or different?

Answer 2

The atoms in different elements are not the same.

Question 3

Where are all the elements arranged?

Answer 3

All elements are arranged in the Periodic Table.

Question 4

What does each element have?

Answer 4

Each element has its own name, symbol, and atomic number.

Question 5

How can you identify particle diagrams that represent an element?

Answer 5

Particle diagrams that have all identical atoms represent an element.

Question 6

Give some examples of everyday elements and how they were named and their uses.

Answer 6

Examples: Oxygen (from Latin ‘oxygène’ meaning acid producer), Gold (from Old English ‘gold’), Iron (used in construction and tools).

Question 7

Name some elements named after scientists or places.

Answer 7

Examples: Curium (after Marie Curie), Einsteinium (after Einstein), Californium (after California).

Question 8

What is a compound?

Answer 8

A compound is a substance made of different kinds of atoms joined together.

Question 9

What is the difference between a mixture of elements and a compound?

Answer 9

In a mixture, different atoms are not chemically joined; in a compound, atoms are chemically bonded.

Question 10

How easy is it to separate atoms in a mixture vs a compound?

Answer 10

Atoms in a mixture are easy to separate, but in a compound, they are difficult to separate.

Question 11

What is a molecule?

Answer 11

A molecule is a particle made when two or more atoms join.

Question 12

What do you call a molecule with all the same kind of atoms?

Answer 12

An element molecule.

Question 13

What do you call a molecule containing different kinds of atoms?

Answer 13

A compound molecule.

Question 14

Name compounds made from two elements where the name ends in ‘-ide’.

Answer 14

Examples: Sodium chloride, carbon dioxide, hydrogen chloride.

Question 15

What happens when different atoms join to form a compound?

Answer 15

Energy is given out, usually in the form of heat and light.

Question 16

Describe an experiment where compounds were made.

Answer 16

Combining hydrogen and oxygen gases to form water.

Question 17

What must happen to break down a compound?

Answer 17

Energy must be put in to separate the atoms.

Question 18

Describe an experiment where you broke down a compound into its elements.

Answer 18

Electrolysis of water to separate hydrogen and oxygen gases.

Question 19

What is the atomic number of an element?

Answer 19

How the periodic table is organised into rows and columns as well as the number of protons in the nucleus.

Question 20

Why do elements have symbols?

Answer 20

To provide a short, universal way to represent elements.

Question 21

What is happening when an iron post rusts?

Answer 21

A chemical change is occurring.

Question 22

What is the smallest particle from which all matter is made?

Answer 22

Atom

Question 23

What do chemical reactions produce?

Answer 23

New substances

Question 24

What is an endothermic reaction?

Answer 24

An endothermic reaction is a chemical reaction that takes in heat energy from its surroundings, making the surroundings feel colder.

Question 25

What is a chemical reaction that releases heat called?

Answer 25

Exothermic

Question 26

What are the general physical properties of metals?

Answer 26

Metals are typically shiny (lustrous), good conductors of heat and electricity, malleable, and ductile.

Question 27

Are metals generally solid, liquid, or gas at room temperature?

Answer 27

Most metals are solid at room temperature, except mercury.

Question 28

In the periodic table, what is a group?

Answer 28

A column of elements with similar chemical properties.

Question 29

What is precipitation in chemistry?

Answer 29

The formation of a solid from a solution during a chemical reaction.

Question 30

What is the only metal that is liquid at room temperature?

Answer 30

Mercury (Hg).

Question 31

Why is mercury unique among metals?

Answer 31

It is the only metal that is liquid at room temperature.

Question 32

What are the general physical properties of non-metals?

Answer 32

Non-metals are usually dull, poor conductors of heat and electricity, brittle in solid form, and not ductile.

Question 33

Are non-metals generally solid, liquid, or gas at room temperature?

Answer 33

Non-metals can be solid (e.g., sulfur), liquid (e.g., bromine), or gas (e.g., oxygen) at room temperature.

Question 34

What is the only non-metal that is liquid at room temperature?

Answer 34

Bromine (Br2).

Question 35

Are non-metals generally sonorous?

Answer 35

No.

Question 36

Sonorous

Answer 36

A material that produces a ringing sound when struck.

Question 37

Ductile

Answer 37

A material that can be drawn out into a thin wire without breaking.

Question 38

Malleable

Answer 38

A material that can be hammered or rolled into thin sheets without breaking.

Question 39

Physical Property

Answer 39

A characteristic that can be observed or measured without changing the substance (e.g., color, melting point, density).

Question 40

Chemical Property

Answer 40

A characteristic that describes a substance's ability to change into a new substance (e.g., flammability, reactivity).

Question 41

Example of Physical Property

Answer 41

Melting point – it can be observed without changing the substance.

Question 42

Example of Chemical Property

Answer 42

Flammability – it describes how a substance reacts with oxygen to form a new substance.

Question 43

Change in Physical Property

Answer 43

Changes like melting, freezing, or breaking – the substance stays the same.

Question 44

Change in Chemical Property

Answer 44

Changes like burning or rusting – the substance becomes something new.

Question 45

What is effervescence?

Answer 45

Bubbles seen in a chemical or physical reaction.

Question 46

Naming Compounds Ending in -ide

Answer 46

Used when a compound contains only two elements. The second element's name ends in -ide (e.g., sodium chloride).

Question 47

Naming Compounds Ending in -ate

Answer 47

Used when a compound contains three or more elements, one of which is oxygen (e.g., copper sulfate).

Question 48

Naming Compounds Ending in -ite

Answer 48

Used for compounds similar to -ate compounds but with less oxygen (e.g., sulfite has less oxygen than sulfate).

Question 49

Element That Keeps Its Name in a compounds name

Answer 49

The first element in the compound usually keeps its name (e.g., sodium in sodium chloride).

Question 50

Element That Changes Its Ending in a compounds name

Answer 50

The second element in the compound changes to -ide, -ate, or -ite depending on the number of elements and presence of oxygen.

Question 51

Identifying Elements in a Compound

Answer 51

Look at the chemical formula and match symbols to elements (e.g., H2SO4 contains hydrogen, sulfur, and oxygen).

Question 52

How to Recognise -ide Compounds

Answer 52

Only two elements are present and the second one ends in -ide.

Question 53

How to Recognise -ate or -ite Compounds

Answer 53

Three or more elements are present, including oxygen. Use -ate for more oxygen, -ite for less.

Question 54

Identifying Elements from the Compound Name

Answer 54

Look at the root of each part of the name. The first part tells you the main element. The ending (-ide, -ate, -ite) helps identify the second element and if oxygen is present (e.g., 'sodium chloride' contains sodium and chlorine).