4.1 A Simple Model Of The Atom Symbols Relative Atomic Mass Electronic Charge And Isoptopes

Question 1

What are all substances made of?

Answer 1

Atoms

Question 2

What is an atom?

Answer 2

The smallest part of an element that can exist

Question 3

How are each atoms of each element represented?

Answer 3

By a chemical symbol

Question 4

How many different elements are there?

Answer 4

About 100

Question 5

Where are elements shown?

Answer 5

In the periodic table

Question 6

How are compounds formed from elements?

Answer 6

By chemical reactions

Question 7

What do chemical reactions always involve?

Answer 7

The formation of one or more new substances and often involve a detectable energy change

Question 8

What do compounds contain?

Answer 8

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

Question 9

How can compounds be separated into elements?

Answer 9

By chemical reactions

Question 10

What does a mixture consist of?

Answer 10

2 or more elements or compounds not chemically combined together

Question 11

In a mixture are the chemical properties of each substance changed or unchanged?

Answer 11

Unchanged

Question 12

How can mixtures be separated?

Answer 12

By physical processes such as filtration crystallisation simple distillation, fractional distillation and chromatography

Question 13

Do the physical processes involve chemical reactions and new substances being formed?

Answer 13

No

Question 14

Describe the process of filtration?

Answer 14

Pour the mixture of solid and liquid through the filter paper in a funnel.
The filter paper separates the solvent (liquid) from the solute (solid).
The clear liquid (filtrate) is obtained in the beaker and the solid (residue) traps on the paper.

Question 15

Describe the process of crystallisation

Answer 15

The solution is heated in an open container.
The solvent molecules start evaporating, leaving behind the solutes.
When the solution cools, crystals of solute start accumulating on the surface of the solution.
Crystals are collected and dried as per the product requirement.

Question 16

Describe the process of distillation

Answer 16

Salt solution is heated.
Water evaporates and its vapours rise. The water vapour passes into the condenser, where it cools and condenses. Liquid water drips into a beaker.
All the water has evaporated from the salt solution, leaving the salt behind.

Question 17

Describe the process of chromatography

Answer 17

Start by drawing a baseline on the chromatography paper using a pencil. …
Place a small spot of the sample mixture on the baseline.
Pour the solvent into a beaker. …
Allow the solvent to slowly travel upwards through the paper, taking with it a few soluble pigments from the sample mixture.

Question 18

Describe the process of fractional distillation

Answer 18

Step 1:- The mixture of liquids is heated in a round-bottomed flask, and the vapours rise and enter the fractionating column.
Step 2:- The vapours then move to the condenser where the temperature is low.
Step 3:- The vapours cool down and get converted into liquid form.

Question 19

What is fractional distillation used to separate?

Answer 19

Miscible liquids

Question 21

What were atoms thought to be before the discovery of the electron?

Answer 21

To be tiny spheres that could not be divided

Question 22

What did the discovery of the electron lead to ?

Answer 22

The plum pudding model of the atom

Question 24

What does the plum pudding model suggest?

Answer 24

The atom is a ball of positive charge with negative electrons embedded in it

Question 25

What was the result of the alpha particle scattering led to?

Answer 25

The conclusion that the mass of an atom was concentrated at the centre and that the nucleus was charged

Question 26

How did Niels Bohr adapt the nuclear model?

Answer 26

By suggesting that electrons orbit the nucleus at specific distances

Question 27

What is a proton?

Answer 27

A tiny positive particle found inside the nucleus of an atom

Question 28

What did later experiments on the atom show?

Answer 28

That the positive charge of any nucleus could be subdivided into a whole number of smaller particles,each particle having the same amount of positive charge

Question 29

What did the experimental work of James Chadwick provide?

Answer 29

The evidence to show the existence of neutrons within the nucleus

Question 30

What is a nucleus?

Answer 30

The very small and dense central part of an atom that contains protons and neutrons

Question 31

What is a neutron?

Answer 31

A dense particle found inside the nucleus of an atom . It is electrically neutral carrying no charge

Question 32

What is an electron?

Answer 32

A tiny particle with a negative charge . Electrons orbit the nucleus of atoms or ions in shells

Question 33

Who discovered the electron lead?

Answer 33

Jo Thompson

Question 34

Who discovered the nucleus and protons?

Answer 34

Rutherford

Question 35

What are the relative electrical charges of protons neutrons and electrons?

Answer 35

+1 0 -1

Question 36

What charge do atoms have overall?

Answer 36

No charge

Question 37

What are the number of electrons in an atom equal to?

Answer 37

The number of protons

Question 38

What are the number of protons in an atom of an element known as?

Answer 38

Atomic number

Question 39

All atoms of a particular element have the same number of what?

Answer 39

Protons

Question 40

What do atoms have approximately a radius of ?

Answer 40

About 0.1nm (1 x 10 to the power of -10m)

Question 41

What are the relative masses of protons , neutrons and electron?

Answer 41

1 1 very small

Question 42

What is the sum of the protons and neutrons in an atom known as?

Answer 42

Mass number

Question 43

What are isotopes?

Answer 43

Atoms of the same element that have the same number of protons but different number of neutrons

Question 44

How do find the number of neutrons?

Answer 44

Mass number - atomic number

Question 45

What is an ion ?

Answer 45

A charged particle produced by the loss or gain of electrons

Question 46

What is the relative atomic mass of an element?

Answer 46

An average value that takes account of the abundance of the isotopes of the element

Question 48

How is the periodic table arranged?

Answer 48

In order of atomic number and so that elements with similar properties are in columns known as groups

Question 49

Why is the periodic table called the periodic table?

Answer 49

Because similar properties occur at regularintervals

Question 50

What do elements in the same group in the periodic table share?

Answer 50

The same number of electrons in their outer shells and this gives them similar properties

Question 51

Before the protons neutrons and electron were discovered how did scientists classify the elements?

Answer 51

By arranging them in order of their atomic weights

Question 52

What happened if the strict order of atomic weights was followed for the periodic table?

Answer 52

Some elements were placed in appropriate groups

Question 53

How did Mendeleev over come some of the problems on the periodic table?

Answer 53

By leaving gaps for elements that he thought had not been discovered and in some places changed the order based on atomic weights

Question 54

What were the gaps in the periodic table filled by?

Answer 54

Elements with properties predicted by Mendeleev were discovered and filled the gaps

Question 55

What made it possible to explain why the order based on atomic weights was not always correct?

Answer 55

Isotopes

Question 56

What are metals?

Answer 56

Elements that react to form positively ions

Question 57

What are non metals?

Answer 57

Elements that do not form positive ions

Question 58

What are the majority of elements?

Answer 58

Metals

Question 59

Where are metals found in the periodic table?

Answer 59

To the left and towards the bottom of the periodic table

Question 60

Where are non metals found in the periodic table?

Answer 60

Towards the right and top

Question 61

What are the elements in group 0 called?

Answer 61

Noble gases

Question 62

What some properties of noble gases ?

Answer 62

They are unreactive and do not easily form molecules

Question 63

Why don’t noble gases form molecules easily?

Answer 63

Because their atoms have stable arrangements of electrons

Question 64

How many electrons are there in the outer shell for noble gases?

Answer 64

8 except from helium which has 2

Question 65

How do the boiling point of noble gases increase ?

Answer 65

With increasing relative atomic mass

Question 66

What are the elements in group 1 known as ?

Answer 66

Alkali metals

Question 67

Why do alkali metals have characteristic properties?

Answer 67

Because of the single electron in their outer shells

Question 68

What happens when alkali metals react with water ?

Answer 68

The metal floats around the water fizzing which happens because the metal reacts with the water to form hydrogen gas

Question 69

What happens when u react potassium with water?

Answer 69

Reacts vigorously with water that the hydrogen produced ignites with a lilac flame

Question 70

What happens when alkali metals react with chlorine?

Answer 70

They react vigorously with chlorine and produce metal oxides

Question 71

How does the reactivity of alkaline metals increase?

Answer 71

With increasing relative atomic mass

Question 72

What are the elements in group 7 known as?

Answer 72

Halogens

Question 73

Why do group 7 metals have similar reactions?

Answer 73

Because the all have 7 electrons in their outer shells

Question 74

What are halogens and what do they consist of?

Answer 74

Non metals and consist of molecules made of pairs of atoms

Question 75

What happens to halogens with increasing relative atomic mass?

Answer 75

The higher its relative molecular mass melting point and boiling point

Question 76

What happens to the reactivity of ehalogens with increasing relative atomic mass?

Answer 76

It decreases

Question 77

What can a more reactive halogen do to a less reactive halogen from an aqueous solution of its salt?

Answer 77

It can displace it

Question 78

What happens to halogens when reacted to metals?

Answer 78

They form ions with a single negative charge in their ionic compounds with metals

Question 79

What happens to halogens when reacted with a non metals ?

Answer 79

They form covalent compounds by sharing electrons with other non metals

Question 80

Where are transition elements?

Answer 80

Metals with similar properties which are different from those of the elements in group 1

Question 81

What are the difference between transition metals and group 1 metals?

Answer 81

Transition metals have higher melting point and density Stronger and harder Less reactive Do not react vigorously with water or oxygen Can form ions with different charges in compounds that are often coloured Important industrial catalyst

Question 82

What do many transition metals have ?

Answer 82

Ions with different charges form coloured compounds and are useful as catalysts