Atomic Structure And The Periodic Table

Question 1

What’s an atom

Answer 1

An atom is the smallest part of an element that can exist. All substances are made of atoms.

Question 2

How many elements are there?

Answer 2

There are about 100 different elements.

Question 3

What are compounds formed from?

Answer 3

Compounds have from 2 or more different elements chemically combined in a fixed proportion

Question 4

What can a compound be separated into?

Answer 4

Compounds can only be separated into elements by chemical reactions

Question 5

What is a mixture?

Answer 5

A mixture consists of two or more elements or compounds, not chemically bonded together

Question 6

What’s the charge of an electron?

Answer 6

-1

Question 7

What’s the relative mass of a neutron?

Answer 7

1

Question 8

What’s the relative mass of an electron?

Answer 8

Very small or 0

Question 9

What’s the charge of a neutron?

Answer 9

Neutral or 0

Question 10

What’s the relative mass of a proton?

Answer 10

1

Question 11

What does the ‘mass number’ of an atom equal to?

Answer 11

protons + neutrons

Question 12

What does the ‘atomic number’ of an atom tell you?

Answer 12

The number of protons in an atom has

Question 13

What’s the charge of a proton?

Answer 13

1

Question 14

How can you work out how many neutrons an atom has

Answer 14

Number of neutrons = mass number - atomic number

Question 15

How can mixture be separated by physical processes?

Answer 15

These are physical processes that do not involve chemical reactions and no new substances are made.

• Filtration
• Crystallization
• Simple distillation
• fractional distillation
• Chromatography

Question 16

Describe and explain filtration? Give examples.

Answer 16

It is used to separate and insoluble solid from a liquid.
Eg. Are useful for separating a mixture of sand and water, or access reactant from a solution. Filtration works because the filter paper has tiny holes or pores in it.

Question 17

Describe and explain crystallization. Give examples.

Answer 17

A process which helps to separate a pure solid from a solution and it’s crystal form
Eg. The salt we get from seawater can have many impurities in it.

Question 18

Describe and explain simple distillation. Give some examples.

Answer 18

It is used to separate a solvent from a solution. When the solution is heated the solvent vapor evaporates from the solution. Ex. Pure water from sea water

Question 19

Describe and explain Fractional distillation. Give examples.

Answer 19

Used to separate different liquids from a mixture of liquids. It is useful for separating ethanol from a mixture of ethanol and water, and for separating different fractions from crude oil

Question 20

Describe and explain chromatography. Give examples.

Answer 20

used to separate mixtures of soluble substances (separating components of a mixture.) ex. coloured substances such as food colourings, inks, dyes

Question 21

Before the discovery of electrons, what were atoms thought to be?

Answer 21

Atoms were thought to be tiny spears that could not be divided

Question 22

What did the discovery of the electron lead to?

Answer 22

It led to the plum pudding, model of the atom

Question 23

What was the plum pudding Model suggested to be

Answer 23

It was suggested that the atom is a ball of positive charge with negative electrons embedded in it

Question 24

What was replaced instead of the plum pudding model

Answer 24

The nuclear model

Question 25

What did the alpha practical lead to?

Answer 25

It led to the conclusion that the mass of an atom was concentrated at the center (nucleus) and that the nucleus was charged.

Question 26

What’s the difference between the plum pudding model of the atom and the nuclear model of the atom?

Answer 26

In the plum pudding model has a positive sphere with negative charge randomly placed within the sphere and there is no empty space. In the nuclear model there is a central positive tiny nucleus with mostly empty space and lots of negative charges .

Question 27

Why did the new evidence from the scattering experiment lead to a change in the atomic model?

Answer 27

Because the mass of an atom is concentrated at the center (nucleus) and that the nucleus was charged. This lead to the plum pudding model being replaced by the Nuclear model.

Question 28

In an atom what are the number of electrons equal to?

Answer 28

The number of protons in the nucleus

Question 29

Do atoms have an electric charge

Answer 29

No. Atoms have no overall electric charge.

Question 30

What are the number of protons in an atom of an element equal to?

Answer 30

It is the atomic number

Question 31

Do all atoms of a particular element, have the same number of protons. Yes or no?

Answer 31

Yes

Question 32

Atoms are very small. What is the radius of an atom

Answer 32

The atoms radius is about 0.1 nm (1 x 10^-10m)

Question 33

Where are almost all of the masses of an atom in?

Answer 33

The nucleus

Question 34

Atoms of the same element can have different numbers of neutrons. What are these atoms called?

Answer 34

isotopes of that element

Question 35

What are isotopes?

Answer 35

Isotopes are different forms of the same element, which have the same number of protons, but a different number of neutrons (same number of protons but different mass numbers)

Question 36

What is the formula of the relative atomic mass?

Answer 36

Relative atomic mass(Ar) = sum of (isotope abundance x isotope mass number) / sum of abundance of all the isotopes

Question 37

What is an element?

Answer 37

An element is a substance made up of only one type of atom.

Question 38

Describe atoms using the nuclear model

Answer 38

Atoms are consists of a tiny central nucleus that is dense and positively charged the nucleus is surrounded by negatively charged electrons most of the atom is empty space.

Question 39

The radius of a nucleus is less than the atom. What’s the radius of a nucleus?

Answer 39

1×10^ -14

Question 40

How did scientists attempt to classify the elements before the discovery of protons, neutrons and electrons

Answer 40

Scientists would arrange them in order of their atomic weights 

Question 41

Elements that react to form positive ions are what

Answer 41

Metals

Question 42

Elements that do not form a positive ion are what

Answer 42

Non-metals

Question 43

How many electrons in the outer shell do noble gases have

Answer 43

8, except for HELIUM which has only 2 electrons

Question 44

The boiling point noble gases increase What else increases?

Answer 44

The relative atomic mass (Going down the group)

Question 45

What are elements in group one of the periodic table known as

Answer 45

Alkali metals that have there characteristic properties because of the single electron in the outer shell

Question 46

In group one is the reactivity of the elements increase. going down or up the group?

Answer 46

Down

Question 47

What are the elements in group 7 known as

Answer 47

Halogens

Question 48

What is similar between all halogens

Answer 48

They all have similar reactions because they all have seven electrons in the outer shell

Question 49

Halogens are non-metals what do they consist of

Answer 49

molecules made of pairs of atoms

Question 50

Further down group 7 it has a higher…

Answer 50

Relative molecular mass, melting point and boiling point

Question 51

What happens to the reactivity in group 7

Answer 51

The reactivity of the elements decrease going down the group

Question 52

In the early periodic table how were the elements set up

Answer 52

The elements were set by the atomic weight

Question 53

Explain the difference between nonmetals and metals

Answer 53

Metals are good conductors of electricity Good conductors of heat have a high density and are Shiny Nonmetals are dull Have a low melting point Poor conductors of electricity Low density

Question 54

Explain simple distillation

Answer 54

Simple distillation is used to separate a liquid from a solid if we want to keep the liquid

Question 55

Explain fractional destalasation

Answer 55

Fractional destination allows us to separate two different liquids

Question 56

More reactive halogens can be displaced by a

Answer 56

Less reactive halogen from an aqueous solution of its salt

Question 57

What was Niels Bohrs theory

Answer 57

He adapted the nuclear model by suggesting electrons orbit the nucleus at a specific distance

Question 58

After Niels Bohr experiment led to the idea that the positive charge of any nucleus could be subdivided into a whole number of smaller particles what were the name of these particles?

Answer 58

Protons

Question 59

What did James Chadwick Find out

Answer 59

That the nucleus contains neutrons

Question 60

The early periodic table was restricted to the order of the atomic weight then Mendeleev overcame some problems what did he do

Answer 60

Mendeleev left gaps of elements he thought had not been discovered then they became discovered and the knowledge of isotopes made it possible to explain why the order based on atomic weight was not always correct