Atoms, Elements And Compounds 4.1.1.1

Question 1

What are all substances made of?

Answer 1

Atoms

Question 2

An atom is the ———- part of an ——- that can exist

Answer 2

An atom is the smallest part of an element that can exist

Question 3

How many elements are there?

Answer 3

There are about 100 different elements in the periodic table

Question 4

How are compounds formed?

Answer 4

Formed from elements by chemical reactions

Question 5

What do chemical reactions always involve?

Answer 5

Always involve the formation of one or more new substances, and often involve a detectable energy change

Question 6

What do compounds contain?

Answer 6

Compounds contain two or more elements chemically combined in fixed proportions and can be represented by formulae using the symbols of atoms from which they were formed

Question 7

How can compounds be separated?

Answer 7

By chemical reactions (into elements) or electrolysis

Question 8

What are most substances?

Answer 8

Compounds

Question 9

What is a chemical formula?

Answer 9

How compounds are represented by a combination of numbers and chemical symbols

Question 10

Where are the reactants in an equation?

Answer 10

On the left-hand side

Question 11

Where are the products in an equation?

Answer 11

On the right- hand side

Question 13

How does the mass act in a reaction?

Answer 13

The total mass of the products of a chemical reaction is always equal to the total mass of the reactants. This is because no atoms are lost or made

Question 14

What is a mixture?

Answer 14

A mixture consists two or more elements or compounds, which are NOT chemically combined

Question 15

What do components of a mixture do?

Answer 15

They retain their own properties

Question 16

What is a benefit of separating mixtures by physical processes?

Answer 16

These processes do not involve chemical reactions, so no new substances are made

Question 17

What is filtration?

Answer 17

Filtration is used to separate soluble solids from insoluble solids

Question 18

What is crystallisation?

Answer 18

Crystallisation is used to obtain a soluble solid from a solution

Question 19

What is simple distillation?

Answer 19

Simple distillation is used to obtain a solvent from a solution

Question 20

What is fractional distillation?

Answer 20

Fractional distillation is used to separate mixtures, in which the components have different boiling points

Question 21

What is chromatography?

Answer 21

Chromatography is used to separate the different soluble, coloured components of a mixture

Question 22

When were electrons discovered and by who?

Answer 22

Thomson discovered electrons in 1898, meaning the representation of the atom, which were thought to be tiny spheres, had to adapt

Question 23

True or False? The atom is overall neutral

Answer 23

True

Question 24

What did Thomson believe?

Answer 24

Thomson thought atoms contained tiny, negative electrons surrounded by a sea of positive charge (the ‘plum pudding’ model).

Question 25

What did Geiger and Marsden carry out and what was the result?

Answer 25

They carried out an experiment in which they bombarded a thin sheet of gold with alpha particles. Although most of the positively charged alpha particles passed straight through the atoms, a tiny number were deflected back towards the source.

Question 26

What did Rutherford conclude from the alpha particle scattering experiment?

Answer 26

Concluded that the positive change in an atom must be concentrated in a very small area. This ‘area’ was named the nucleus and the resulting model became known as the ‘nuclear’ model, replacing the Plum Pudding model.

Question 27

What did Bohr discover?

Answer 27

Bohr deduced that electrons must orbit the nucleus from specific distances, otherwise they would spiral inwards.

Question 28

What did James Chadwick discover?

Answer 28

Provided evidence for neutrons in the nucleus

Question 29

What did later experiments after James Chadwick’s neutron discovery lead to?

Answer 29

Later experiments led to the idea that positive charge of a nucleus could be subdivided into a whole number of smaller particles, each with the same amount of positive charge. These particles are called protons

Question 30

What is the radius of an atom?

Answer 30

0.1 nm or 1 xx 10 -10m

Question 31

Relative mass of a proton

Answer 31

1

Question 32

Relative mass of a neutron

Answer 32

1

Question 33

Relative mass of an electron

Answer 33

Very small

Question 34

Relative charge of a proton

Answer 34

+1

Question 35

Relative charge of a neutron

Answer 35

0

Question 36

Relative charge of an electron

Answer 36

-1

Question 37

Where is most of the mass in an atom?

Answer 37

In the nucleus, however most of the atom is empty space

Question 38

What is the overall charge of an atom?

Answer 38

They have no overall charge because they contain an equal number of protons and electrons

Question 39

What is the atomic number?

Answer 39

The number of protons in an atom

Question 40

What is the mass number?

Answer 40

The sum of the protons and neutrons in an atom

Question 41

What is the equation for the number of neutrons?

Answer 41

Mass number - atomic number

Question 42

What is an isotope?

Answer 42

Isotopes of an element have the same number of protons but a different number of neutrons - the same atomic number, but a different mass number

Question 43

How do atoms become ions?

Answer 43

Atoms gain or lose electrons to become ions - metal atoms lose electrons to form positive ions - non-metal atoms gain electrons to form negative ions

Question 44

What is the electron configuration of an atom?

Answer 44

Shows how the electrons are arranged around the nucleus in shells

Question 45

What is a nanometer (nm) ?

Answer 45

One billionth of a metre

Question 46

Who first developed the periodic table?

Answer 46

John Newlands, in 1864

Question 48

How many elements were originally on the periodic table?

Answer 48

63

Question 49

How did Newlands arrange the periodic table?

Answer 49

He arranged the known elements in order of atomic weight. He noticed periodicity (repeated patterns), although the missing elements caused problems. Strictly following the order of atomic weight created issues meaning elements were in the wrong place.

Question 50

Who improved John Newlands periodic table?

Answer 50

Dimitri Mendeleev

Question 51

How did Mendeleev improve the periodic table? (1869)

Answer 51

He left gaps to allow the discovery of new elements. He also reordered some element

Question 52

How was Mendeleev’s periodic table organised?

Answer 52

Each element was organised in a vertical column or ‘group’ with elements that had similar properties. When subatomic particles were later discovered, it revealed that Mendeleev had organised his periodic table in order of increasing atomic number.

Question 53

How did Mendeleev use his periodic table?

Answer 53

To predict the existence and properties of new elements

Question 54

What are group 0 elements known as?

Answer 54

Noble gases

Question 55

What do Noble gas atoms have?

Answer 55

Full outer shells of electrons, meaning they are very stable, making them very unreactive non-metals

Question 57

What happens to the boiling point as you go down group 0?

Answer 57

It increases

Question 58

What are elements in group 1 known as?

Answer 58

The alkali metals