End of Term 2 Test

Question 1

What is an Isotope

Answer 1

Atoms of an element that have the same number of protons but a different number of neutrons in the nucleus.
For example, carbon atoms have 6 neutrons in their nucleus, but some have 7 and some have 8

Question 2

Radioactive decay of isotopes

Answer 2

Some isotopes become unstable when the ratio of neutrons to protons is too high,
they may undergo radioactive decay to become more stable.
There are 3 types of radioactive or nuclear decay: Alpha Decay, Beta Decay, Gamma radiation

Question 3

Alpha Decay

Answer 3

Symbol: a
Nucleus ejects an alpha particle (contains 2 neutrons and 2 protons – similar to a helium atom), occurs in an atom with very heavy nuclei
- Can be stopped/penetrated by a piece of paper
Uses: Many smoke detectors contain americium-241, which releases alpha radiation and helps detect smoke.
Penetration power: Low energy

Question 4

Beta Decay

Answer 4

Symbol: B
Nucleus ejects a beta particle (1 electron)
- Can be stopped/penetrated by aluminium foil
Uses: Beta-radiation emitters can be used as cancer treatment
Penetration power: High energy

Question 5

Gamma radiation

Answer 5

Symbol: Y
High energy electromagnetic rays released from the nucleus 
- Can be stopped/penetrated by lead
Uses: sterilise medical equipment
Penetration power: High energy

Question 6

Electron shell diagrams

Answer 6

2 electrons in the first shell
8 in the second shell
up to calcium 8, above calcium 18 in the third shell
32 in the fourth shell

Question 7

Protons

Answer 7

Positively Charged (+1), In the nucleus, relative mass 1

Question 8

Neutrons

Answer 8

Neutral, In the nucleus, relative mass 1

Question 9

Electrons

Answer 9

Negatively Charged, Around the nucleus, 1/1840

Question 10

What does a PH scale/ Universal indicator do?

Answer 10

A scale that measures the acidity to find an acid or a base

Question 11

What colour does litmus paper become when met with an acidic solution

Answer 11

Red

Question 12

What colour does litmus paper become when met with a base solution

Answer 12

Blue

Question 13

Between what rating are Bases on the Ph scale

Answer 13

8-14

Question 14

Between what ratings are Acids on the Ph scale

Answer 14

0-6

Question 15

What rating is neutral on the Ph scale

Answer 15

7

Question 16

Bases

Answer 16

Taste bitter, feel slippery and soapy, if they dissolve in water it is alkalis (base)

Question 17

Acids

Answer 17

• Taste sour, produce a prickling or burning sensation if come in contact with your
  skin, all contain at least one hydrogen atom and tend to react with many metals
• Can be strong or weak. Concentrated acids can burn you and would show lower on the pH scale while weaker acids you can eat and drink like an orange and would show more neutral

Question 18

Atomic number

Answer 18

The number that represents the total number of protons in the atomic nucleus

Question 19

Mass number

Answer 19

The number that represents the total number of protons and neutrons in the atomic nucleus

Question 20

Atomic Theory: Dalton

Answer 20

All matter is made of atoms. Atoms are indivisible and indestructible. All atoms of a given element are identical in mass and properties. Compounds are formed by a combination of two different atoms.

Question 21

Atomic Theory: Thompson

Answer 21

His research in Cathode rays led to the discovery of an electron. He pursued further investigations into atomic structure. He also discovered the isotope and the subatomic particle. This is the plum pudding model

Question 22

Atomic Theory: Rutherford

Answer 22

The Rutherford model was used to describe an atom. He overturned Thompsonʼs theory and found an atom has a tiny and heavy nucleus. He found major portion of the atom is empty, the centre is called the nucleus and the positively charged particles are found in the nucleus

Question 23

Acid + Base (Neutralisation) Reaction:

Answer 23

Acid + Base -> Salt + Water
When an acid and a base combine, they will react in which is called a neutralisation reaction. This creates a new product and creates a new pH. The product will change depending on the base.
E.g. Magnesium hydroxide + Hydrochloric acid ̶> Magnesium chloride + water
= MgHO + HCl ̶> MgCl + H2O

Question 24

Acid + Carbonate Reaction

Answer 24

Acid + Carbonate -> Salt + Water + Carbon dioxide
Carbonates release carbon dioxide which can be seen as bubbling. Water and Carbon dioxide are formed because the carbonate ions react with the H+ ions from the acid
E.g. Nitric acid + Copper Carbonate -> Copper nitrate + salt + carbon dioxide

Question 25

Salt

Answer 25

compound that contains a metal (positive) ion and a non-metal (negative) ion
E.g. Potassium chloride is the salt produced when hydrochloric acid reacts with potassium hydroxide.

Question 26

Acid + (Reactive) Metal Reaction:

Answer 26

Acid + Metal -> Salt + Hydrogen
When acids react with metals they produce hydrogen gas and a salt. The salt that forms in the combination of the positive metal ion from the base and the negative non-metal ion from the acid.
E.g. Hydrochloric acid + Magnesium -> Magnesium chloride + Hydrogen

Question 27

Identify the salts produced in common acids

Answer 27

• Hydrochloric acid (HCI) produces chloride salts
• Nitric acid (HNO3) produces nitrate salts
• Sulfuric Acid (H2SO4) produces sulfate salts

Question 28

Describe the tests for Carbon dioxide and Hydrogen gas

Answer 28

Carbon dioxide: Lime water test or extinguishes a lit paper

Hydrogen gas: Pop test

Question 29

The current accepted model of an atom

Answer 29

• Nucleus consists of protons and neutrons
• Protons are positively charged particles
• Neutrons have no charge
• The mass of an atom is mostly because of the mass of the nucleus
• Electrons (negatively charged particles) move around the space around the nucleus
• Overall, atoms are neutral (have no charge) because there is always the same number of positive and negative electrons in any atom