Unit B - Atoms, Elements And Compounds

Question 1

Matter

Answer 1

Anything that has mass and volume

Question 2

Mass

Answer 2

A measurement of the quantity of matter in an object.

Question 3

Volume

Answer 3

A measure of how big an object is or how much space a fluid takes up.

Question 4

Sublimation

Answer 4

A change from a solid to a gas

Question 5

Deposition

Answer 5

A change from gas into a solid

Question 6

Melting point

Answer 6

The temperature at which a solid turns into a liquid

Question 7

Freezing point

Answer 7

The point at which a which a liquid turns into a solid (same temperature as melting point)

Question 8

Particle Theory of Matter

Answer 8

• All matter is composed of very tiny particles
• All particles have spaces between them
• Particles present in matter are always in motion
• The particles in a substance attract each other

Question 9

Property

Answer 9

A characteristic that describes a substance

Question 10

Two main ways to classify matter

Answer 10

• Pure Substances

- Mixtures

Question 11

Pure substance

Answer 11

Made up of only one kind of matter and had a unique set of properties such as colour, hardness, boiling point and melting point

Question 12

Element

Answer 12

A substance that cannot be broken down into any simples substance by chemical means

Question 13

Compound

Answer 13

A pure substance made from two or more elements that are combines together chemically

Question 14

Mechanical Mixture

Answer 14

A mixture in which the different substances that make up the mixture are visible

Question 15

Suspension

Answer 15

A cloudy mixture in which tiny particles of one substance are held within another

Question 16

Solution

Answer 16

A mixture in which the different substances that make it up are not individually visible

Question 17

Physical properties

Answer 17

A characteristic of a substance that can be observed or measured

Question 18

List of physical properties

Answer 18

• Colour and Lustre
• Conductivity
• Density
• Ductility
• Hardness
• Malleability
• Viscosity

Question 19

Chemical property

Answer 19

The ability of a substance to change into a new substance or substances

Question 20

Chemical change

Answer 20

A formation of a new substance or substances

Question 21

Chemical reaction

Answer 21

A process in which chemical change occurs

Question 22

Evidence of a chemical change

Answer 22

Change in:

• colour
• odour
• temperature
• the production of light
• the formation of a solid inside a liquid
• the production of a new gas

Question 23

Combustibility

Answer 23

The ability of a substance to react quickly with oxygen to produce heat and light

Question 24

List of Chemical Properties

Answer 24

• Absorbs heat during reaction
• Combustible
• Forms has when heated
• Reacts with acid
• Reacts with water
• Emits heat during reaction
• Emits light durning reaction
• Forms a precipitate (solid) in a solution

Question 25

Cohesion

Answer 25

When matter sticks to itself

Question 26

Adhesion

Answer 26

When matter sticks to other substances

Question 27

Atom

Answer 27

The smallest part of an element that has all the elements properties

Question 28

Atomic Theory

Answer 28

- All matter is made up of small, indivisible particles called atoms. - All the atoms of an element are identical in properties such as size and mass - Atoms of different elements have different properties - Atoms of different elements have different properties

Question 29

Protons

Answer 29

Positively charged particles in the atom. In the nucleus

Question 30

Neutrons

Answer 30

The neutral particles in the atom. In the nucleus

Question 31

Electrons

Answer 31

The negatively charged particles in atoms. In the orbit

Question 32

J.J. Thompson

Answer 32

Used cathode ray tube to discover electrons.

Question 33

Ernest Rutherford

Answer 33

Used gold foil to discover nucleus by bouncing positive particles and having them bounce back.

Question 34

James Chadwick

Answer 34

Refined concept of nucleus and discovers neutrons.

Question 35

Characteristics of metals

Answer 35

- shiny or silvery gray in colour - good conductors of electricity and heat and malleable and ductile - some metals (sodium) react explosively with water while others (platinum) won’t react even if mixed with strong acids

Question 36

Characteristics of non-metals

Answer 36

Only 17 elements are non-metals. | At room temp, 11 are gases, 5 are solids and 1 (bromine) is red /brown liquid.

Question 37

Metalloids

Answer 37

The metalloids are elements with metallic and non-metallic properties. Semiconductors and silicon is the most common metalloid and is shiny and grey but brittle.

Question 38

Iron (Fe)

Answer 38

Quite common and once separated from ore and can be used and combined with a wide range of items. Can be made Fairly resistant to corrosion.

Question 39

Carbon (C)

Answer 39

Carbon exists in many forms including graphite and diamond. Coal is another form of graphite. Carbon is also one of the main building blocks of life.

Question 40

Hydrogen (H)

Answer 40

The most common element of the universe and makes up most of the atoms in stars as well as planets like Jupiter. Hydrogen is also in the core of stars. It’s found in water on earth and is also extremely flammable.

Question 41

Oxygen (O)

Answer 41

Pure oxygen is a gas at room temp. Makes up about 21% of all the air we breathe. Pure oxygen can exist in more than one form. The air we breathe is a form of two oxygen atoms connected.

Question 42

Sodium (Na)

Answer 42

Sodium is a metal and it shares many properties with iron. Sodium metal reacts immediately and violently if it contacts either air or water. Usually store in oil where it doesn’t react for a long time. It’s so soft that a knife easily cuts through it and also melts easily.

Question 43

Chlorine (Cl)

Answer 43

Chlorine, a non-metal, is a yellow green gas at room temp. High concentrations of the gas are toxic and will quickly destroy lung tissue at lower concentrations is extremely useful as a disinfectant and used to kill bacteria.

Question 44

Atomic number

Answer 44

The number of protons in the atom of an element.

Question 45

Atomic mass

Answer 45

The average mass of an elements atoms given in atomic mass units (amu).

Question 46

Ion charge

Answer 46

The electric charge an atom takes on when it loses or gain electrons.

Question 47

Ion

Answer 47

An atom or group of atoms that has lost or gained electrons.

Question 48

Period

Answer 48

The seven horizontal rows in the periodic table.

Question 49

Group (chemical family)

Answer 49

``` The 18 vertical columns in the periodic table. Important ones - alkali metals - alkaline earth metals - halogens - noble gases ```

Question 50

Alkali metals

Answer 50

Group 1: Li, Na, K, Rb, Cs All of them are silvery gray, malleable and ductile. They all have low melting points and are soft enough to cut with a knife and react easily with water and air. Gradual change descending in an increase in density, and softness. Also they melting points get lower and lower.

Question 51

Halogens

Answer 51

Group 17: F, Cl, Br, I All are non metals and have a noticeable colour. All are very reactive. From the first element (fluorine) down to iodine the colour intensity and melting points increase.

Question 52

Noble Gases

Answer 52

Group 18: He, Ne, Ar, Kr, Xe, Rn All exist as colourless gases but glow bright if an electric current is passed through. Usually not chemically reactive Density of gases increases from helium to radon.

Question 53

Ionic compounds

Answer 53

Pure substances consisting of one metal (lose) and one non-metal (gain) with the following properties: - high melting points - form crystals - dissolve in water to form solutions that conduct electricity

Question 54

Molecular compounds

Answer 54

A non-metal and non-metal and share the following properties: - can be in any of the three states at room temp - usually good insulators but poor conductors - relatively low boiling points

Question 55

Ionic compounds formula

Answer 55

Name of metal & name of non-metal + ide

Question 56

Multivalent element

Answer 56

Element with more than one stable ion e.g. Iron

Question 57

Polyatomic ions

Answer 57

``` A group of atoms of different elements that act as a single ion : Hydroxide OH- Carbonate CO2- 3 Phosphate PO 3- 4 Sulphate SO 2- 4 Sulphite SO 2- 3 Nitrate NO- 3 Chlorate ClO- 3 Bicarbonate HCO- 3 Ammonium NH+ 4 Potassium hydroxide KOH ```

Question 58

Molecular compounds formula

Answer 58

First element & prefix+second element

Question 59

Effects of mercury poisoning

Answer 59

Effects on nervous system and muscles. Rashes, numbness, tremors, slurred speech, tooth loss, reproductive problems and birth defects.

Question 60

CFC

Answer 60

Chlorofluorocarbons are non-toxic and non-flammable but destroy the ozone layer. Banned in 1987 by many countries after a hole in the ozone was found.