Unit B - Atoms, Elements And Compounds Flashcards Preview

Grade 9 Science Exam > Unit B - Atoms, Elements And Compounds > Flashcards

Flashcards in Unit B - Atoms, Elements And Compounds Deck (60)
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1
Q

Matter

A

Anything that has mass and volume

2
Q

Mass

A

A measurement of the quantity of matter in an object.

3
Q

Volume

A

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

4
Q

Sublimation

A

A change from a solid to a gas

5
Q

Deposition

A

A change from gas into a solid

6
Q

Melting point

A

The temperature at which a solid turns into a liquid

7
Q

Freezing point

A

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

8
Q

Particle Theory of Matter

A
  • 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
9
Q

Property

A

A characteristic that describes a substance

10
Q

Two main ways to classify matter

A
  • Pure Substances

- Mixtures

11
Q

Pure substance

A

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

12
Q

Element

A

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

13
Q

Compound

A

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

14
Q

Mechanical Mixture

A

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

15
Q

Suspension

A

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

16
Q

Solution

A

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

17
Q

Physical properties

A

A characteristic of a substance that can be observed or measured

18
Q

List of physical properties

A
  • Colour and Lustre
  • Conductivity
  • Density
  • Ductility
  • Hardness
  • Malleability
  • Viscosity
19
Q

Chemical property

A

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

20
Q

Chemical change

A

A formation of a new substance or substances

21
Q

Chemical reaction

A

A process in which chemical change occurs

22
Q

Evidence of a chemical change

A

Change in:

  • colour
  • odour
  • temperature
  • the production of light
  • the formation of a solid inside a liquid
  • the production of a new gas
23
Q

Combustibility

A

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

24
Q

List of Chemical Properties

A
  • 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
25
Q

Cohesion

A

When matter sticks to itself

26
Q

Adhesion

A

When matter sticks to other substances

27
Q

Atom

A

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

28
Q

Atomic Theory

A
  • 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
29
Q

Protons

A

Positively charged particles in the atom. In the nucleus

30
Q

Neutrons

A

The neutral particles in the atom. In the nucleus

31
Q

Electrons

A

The negatively charged particles in atoms. In the orbit

32
Q

J.J. Thompson

A

Used cathode ray tube to discover electrons.

33
Q

Ernest Rutherford

A

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

34
Q

James Chadwick

A

Refined concept of nucleus and discovers neutrons.

35
Q

Characteristics of metals

A
  • 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
36
Q

Characteristics of non-metals

A

Only 17 elements are non-metals.

At room temp, 11 are gases, 5 are solids and 1 (bromine) is red /brown liquid.

37
Q

Metalloids

A

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.

38
Q

Iron (Fe)

A

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.

39
Q

Carbon (C)

A

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.

40
Q

Hydrogen (H)

A

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.

41
Q

Oxygen (O)

A

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.

42
Q

Sodium (Na)

A

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.

43
Q

Chlorine (Cl)

A

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.

44
Q

Atomic number

A

The number of protons in the atom of an element.

45
Q

Atomic mass

A

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

46
Q

Ion charge

A

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

47
Q

Ion

A

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

48
Q

Period

A

The seven horizontal rows in the periodic table.

49
Q

Group (chemical family)

A
The 18 vertical columns in the periodic table.
Important ones 
- alkali metals
- alkaline earth metals
- halogens
- noble gases
50
Q

Alkali metals

A

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.

51
Q

Halogens

A

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.

52
Q

Noble Gases

A

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.

53
Q

Ionic compounds

A

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
54
Q

Molecular compounds

A

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
55
Q

Ionic compounds formula

A

Name of metal & name of non-metal + ide

56
Q

Multivalent element

A

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

57
Q

Polyatomic ions

A
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
58
Q

Molecular compounds formula

A

First element & prefix+second element

59
Q

Effects of mercury poisoning

A

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

60
Q

CFC

A

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.