Splitting the Atom

Question 1

What are atoms made of?

Answer 1

Protons, Neutrons and Electrons

Question 2

What is inside the nucleus?

Answer 2

Protons and neutrons.

Question 3

What is the mass number in the periodic table?

Answer 3

The sum of the protons and neutrons in the nucleus

Question 4

What is the atomic number in the periodic table?

Answer 4

The number of electrons and protons in an atom.

Question 5

Where are electrons found?

Answer 5

Orbiting the nucleus

Question 6

What are the charges of the particles in an atom?

Answer 6

Protons are positive, neutrons are neutral and electrons are negative.

Question 7

What charge is the nucleus?

Answer 7

Positive

Question 8

What are the characteristics of a nucleus?

Answer 8

It is very small and dnese and contains protons and neutrons.

Question 9

What are the regions containing electrons called?

Answer 9

Electron shells or clouds

Question 10

How many electrons can the first shell hold?

Answer 10

2

Question 11

How many electrons can the second shell hold?

Answer 11

8

Question 12

How many shells can the third shell hold?

Answer 12

16

Question 13

How do you calculate the number of neutrons of an atom?

Answer 13

Subtract the atomic number from the mass number.

Eg. Iron has a mass number of 56 and an atomic number of 26. 56-26=30 neutrons. Since each atom is neutral, the number of negative electrons=the number of positive protons=26 for Iron

Question 14

How is the periodic table organised?

Answer 14

Horizontal rows called PERIOD and vertical rows called GROUPS

Question 15

How many groups are there in the periodic table?

Answer 15

8 groups

Question 16

What characterises each group?

Answer 16

Each group behaves the same way

Question 17

How do group 1, 2, 7 and 8 behave?

Answer 17

(a) group 1-alkali metals (all react strongly with water) (b) group 2-alkaline earth metals
(c) group 7-halogens (all brightly coloured)
(d) group 8-noble gasses (do not react with anything)

Question 18

What happens when you move from left to right across each period of the periodic table?

Answer 18

The elements from from more metallic to less metallic from left to right.

Question 19

What is on the left hand side of the periodic table?

Answer 19

Metals

Question 20

What is on the right hand size of the periodic table?

Answer 20

Non-metals and metalloids (in between)

Question 21

What is the relationship between groups and the electrons in their outer shell?

Answer 21

Elements in the same group have the same number of electrons in their outer shell (why they behave the same way)

E.g Group 1 elements all have one electron in their outer shell, group 2 elements all have two electrons in their outer shell etc.

Question 22

What is the relationship between the period and the electron shells?

Answer 22

The period that an element belongs to corresponds to the number of shells for each atom.

e.g Lithium is in period 2 indicating it has two shells, one shell has 2 electrons and the other shell has 1 electron

Question 23

What are the 4 trends of the periodic table?

Answer 23

• Atomic number and mass number: both increase across a period and down a group
• Atoms get bigger down a group and smaller across a period
• Metals become more reactive down a group
• Across a period metals become less reactive.

Question 24

What is the aim of each atom?

Answer 24

Each atom tries to get 8 electrons in its outer shell. This is why the noble gasses (group 8) do not react at all

Question 25

What is a molecule?

Answer 25

A combination of two or more elements

Question 26

What is a molecule of an element?

Answer 26

Molecules composed of the same elements e.g H2 Hydrogen O2 Oxygen

Question 27

What is a molecule of a compound?

Answer 27

Molecules composed of different elements e.g NaCl Sodium Chloride

Question 28

What is the law of conservation of matter?

Answer 28

Matter can neither be created nor destroyed, but merely changed from one form or another. This means that elements can combine to form compounds, that compounds can be decomposed into elements and that compounds can combine together to form different compounds, but the total amount of each element on earth cannot be changed.

Question 29

What is the precipitation reaction?

Answer 29

Mixing 2 soluble liquids results in the formation of an insoluble solid called precipitate. This happens because of ionic attraction of dissolved ions in the liquid

Question 30

What is the decomposition reaction?

Answer 30

When a compound breaks down into 2 or more compounds through heat or electrolysis (using electrical current) e.g h20 > H2 + 02

Question 31

What happens in radioactivity?

Answer 31

Certain elements give off radiation when they decay or break down. This is as they have unstable nuclei which will break down to a more stable one releasing particles and energy from the nucleus.

Question 32

What three kinds of radiation are there in radioactivity?

Answer 32

Alpha particle, beta particle and gamma rays.

Question 33

What happens in nuclear fissions?

Answer 33

Nuclear energy is released when changes are made to the nuclei of atoms. Nuclear fission is splitting heavy atoms into light atoms. When this happens a large amount of energy is released.

Question 34

How are nuclear fissions achieved?

Answer 34

By hitting the nucleus of an unstable neutron with an unstable atom.

Question 35

How is nuclear energy positively used?

Answer 35

Mostly in electricity production, medicine, industry, agriculture, and environment.

Question 36

How is nuclear energy harmful?

Answer 36

Weapons, radiation (causes changes to DNA/cancer, stays in environment for long time, nuclear waste (takes a long time to decay)

Question 37

What are the advantages of using nuclear energy in electricity production?

Answer 37

Does not involve the emission of smoke and carbon dioxide or other pollutants while in use (does not contribute to greenhouse effect) Produces huge amounts of energy from small amounts of fuel, small amount of waste, and is reliable.

Question 38

What are the disadvantages of using nuclear energy?

Answer 38

Creates radioactive waste which is extremely toxic and harmful to both humans and the environment - needs to be stored safely underground, away from earthquakes, flooding, terrorists Alot of money is spent on safety, and building nuclear reactors. The explosion of nuclear weapons such as hydrogen and atomic bombs can lead to massive losses in terms of living and non-living things including the environment Radioactive substances take an extremely long time to be completely decay.