Bk2 Ch2 Atoms

Question 1

Element (definition)

Answer 1

<p>An element is a pure substance composed of only one type of atom.</p>

Question 1

<p>possible ways to break down a substance</p>

Answer 1

<p>burning or using acids or other chemicals.</p>

Question 2

<p>There are how many naturally occurring elements</p>

Answer 2

<p>92</p>

Question 2

<p>There are how many synthetic elements</p>

Answer 2

<p>over 20</p>

Question 3

<p>Name two metals and give examples of their uses</p>

Answer 3

<p>aluminium is used to form cooking utensils, copper for electrical wires and plumbing pipes.</p>

Question 3

<p>Name two non-metals and give examples of their uses</p>

Answer 3

<p>Nitrogen is used for making fertilisers, carbon (diamond) for jewellery and cutting tools.</p>

Question 4

<p>Describe the connection between atoms and elements.</p>

Answer 4

<p>Atoms which are the same make up elements.</p>

Question 4

<p>Most abundant elements on earth</p>

Answer 4

<p>oxygen 47%, silicon 28%, aluminium 8%, iron 5%</p>

Question 5

<p>The Hindenburg airship (or Zeppelin) was filled with the element</p>

Answer 5

<p>hydrogen</p>

Question 5

<p>Of the 106 known elements, how many metals and non-metals?</p>

Answer 5

<p>84 metals, 22 non-metals</p>

Question 6

<p>All metallic elements are solids at room temperature except for</p>

Answer 6

<p>mercury</p>

Question 6

<p>atom (definition)</p>

Answer 6

<p>the smallest piece of a substance that is still that substance.</p>

Question 7

<p>The word ‘atom’ comes from the Greek word</p>

Answer 7

<p>atomos, meaning ‘that which cannot be divided’.</p>

Question 7

<p>What is the lightest atom?</p>

Answer 7

<p>Hydrogen</p>

Question 8

<p>Name two heavy atoms</p>

Answer 8

<p>Hassium, Meitnerium</p>

Question 8

<p>Atoms are made up of…</p>

Answer 8

<p>Protons, neutrons & electrons</p>

Question 9

<p>Name the three naturally occurring isotopes of Hydrogen.</p>

Answer 9

<p>1. protium 2. deuterium 3. tritium</p>

Question 9

<p>Atoms are most stable when…</p>

Answer 9

<p>their outer shells are filled.</p>

Question 10

<p>1 mole = </p>

Answer 10

<p>6.022 x 10^23 (ten to power of 23) </p>

Question 10

<p>1 mole of an element is..</p>

Answer 10

<p>it's atomic weight in grams</p>

Question 11

<p>ion (definition)</p>

Answer 11

<p>a charged atom</p>

Question 11

<p>Metals are</p>

Answer 11

<p>electron donors</p>

Question 12

<p>Non-Metals are</p>

Answer 12

<p>electron acceptors</p>

Question 12

<p>Compound (definition)</p>

Answer 12

<p>A substance formed by two or more elements combined in a fixed ratio.</p>

Question 13

Using examples, identify the two types of compound structures.

Answer 13

Molecule (eg: water H2O, Oxygen O2) and Lattice (eg: Sodium Chloride NaCl, Quartz SiO2)

Question 13

Molecule (definition)

Answer 13

Two or more atoms chemically combined.

Question 14

Lattice (definition)

Answer 14

A regular array of atoms chemically combined.

Question 14

Mixture (definition)

Answer 14

A mixture is a collection of different substances (elements or compounds). These substances are not bonded together and no new substance is formed when they are combined.

Question 15

A physical change occurs when…

Answer 15

a substance changes, but no new substance is formed.

Question 15

Physical changes occur when the state of a substance changes. Eg:

Answer 15

melting, evaporation, freezing, condensing (or a substance is crushed, ground or cut into smaller pieces.)

Question 15

A chemical change or chemical reaction occurs whenever…

Answer 15

a new substance forms.

Question 15

Indications of a chemical change…

Answer 15

Production of bubbles of gas. A change in colour. The production of heat (exothermic) or light. A drop in temperature (endothermic). A solid is formed (precipitate).

Question 15

The substances present before the chemical reaction has occurred are called the…

Answer 15

reactants.

Question 15

The chemicals formed by the reaction are called the…

Answer 15

products.

Question 15

Combination reactions (definition)

Answer 15

where two or more reactants join together to form one new substance.

Question 15

Combination reactions (example)

Answer 15

rusting of a metal: iron + oxygen -> iron oxide

Question 15

Combination reactions are also called…

Answer 15

synthesis reactions.

Question 15

Decomposition reactions (definition)

Answer 15

A single reactant breaking down or decomposing into two or more new substances.

Question 15

Decomposition reactions (example)

Answer 15

Water can be broken down using electricity to produce oxygen gas and hydrogen gas.

Question 15

Precipitation reactions (definition)

Answer 15

when a solid forms when two solutions are mixed together.

Question 15

Combustion reactions (definition)

Answer 15

Combustion reactions happen whenever something burns or explodes.

Question 15

Combustion reactions (example)

Answer 15

Carbon may be burnt to produce carbon dioxide gas. carbon + oxygen -> carbon dioxide

Question 15

Reaction rate can be affected by:

Answer 15

The amount or concentration of reactants. Temperature. Surface area. Catalysts (helper chemicals)

Question 15

Catalyst (definition)

Answer 15

A substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change.

Question 15

What are enzymes?

Answer 15

Special types of catalysts called enzymes are found in our bodies. Digestive enzymes help break down large molecules such as starch into smaller molecules such as glucose.

Question 15

Explain what is meant by each of the following when written in chemical equations: (s), (l), (g), (aq), ->

Answer 15

solid, liquid, gas, aqueous,

Question 15

the atomic number is

Answer 15

the number of protons in the nucleus.

Question 15

the mass number is

Answer 15

the number of protons and neutrons in the nucleus.

Question 15

To find the number of neutrons, you subtract…

Answer 15

the atomic number from the mass number.

Question 15

Number of electrons =

Answer 15

number of protons = atomic number

Question 15

The original idea of a small particle called the atom came from..

Answer 15

the ancient Greeks, some 2000 years ago.

Question 16

In 1808 which English chemist supports the idea of atoms as solid balls?

Answer 16

John Dalton

Question 17

In 1897 who discovers electrons?

Answer 17

Sir Joseph John Thomson (Great Britain)

Question 18

In 1903, who proposes the ‘plum pudding’ model of a positively charged ‘dough’ with negatively charged electrons embedded in it?

Answer 18

Sir Joseph John Thomson (Great Britain)

Question 19

In 1911, who proposes a nuclear model in which negatively charged electrons orbit a positive nucleus, with most of the atom being empty space?

Answer 19

Ernest Rutherford, a New Zealand born physicist and student of Thomson.

Question 20

In 1913, who extends Rutherford’s model to include electron shells?

Answer 20

Niels Bohr, a Danish physicist and assistant to Rutherford.

Question 21

In 1914, who discovers the proton?

Answer 21

Ernest Rutherford

Question 22

In 1932, who discovers neutrons?

Answer 22

James Chadwick (Great Britain)

Question 23

Atoms are mainly what?

Answer 23

empty space.

Question 24

The model of the atom used today is the…

Answer 24

Rutherford–Bohr model.

Question 25

Protons and neutrons have about the same mass, while electrons have…

Answer 25

about 1/2000th the mass of protons and neutrons.

Question 26

In what year were electrons discovered?

Answer 26

1897

Question 27

In what year were protons discovered?

Answer 27

1914

Question 28

In what year were neutrons discovered?

Answer 28

1932