Chemistry Unit Test

Question 1

Matter

Answer 1

Anything that has made and takes up space

Question 2

Physical property

Answer 2

A characteristic or description of a substance that is determined when

Question 3

Chemical Property

Answer 3

A characteristic of a substance that is determined when the composition of the substance is changed and one or more new substances are formed

Question 4

Physical changes

Answer 4

A change of state
Change of form
Easily reversed
No new products formed

Question 5

What are the signs of a chemical change?

Answer 5

Precipitate forms
Bubbles or gas produced 
Change in colour 
Change in odour
Change in energy 
Heat or light formed 
Not easily reversed

Question 6

Formulae

Answer 6

Density = mass/volume 
Mass = density x volume 
Volume = mass/density

Question 7

What are the three subatomic particles

Answer 7

Protons
Neutrons
Electrons

Question 8

How to find number of protons

Answer 8

Atomic number

Question 9

How to find number of neutrons

Answer 9

Mass - atomic number

Question 10

How to find number of electrons

Answer 10

Number of protons

Question 11

Metals

Answer 11

Found on the right of the periodic table

Lustrous, hard, malleable, ductile, conduct heat and electricity

Question 12

Metalloids

Answer 12

Have properties of both metals and non metals

Found along the staircase line

Question 13

Group 1

Answer 13

Alkali Metals

Question 14

Group 2

Answer 14

Alkaline earth metals

Question 15

Group 3-12

Answer 15

Transition metals

Question 16

Group 17

Answer 16

Halogens

Question 17

Group 18

Answer 17

Noble gases

Question 18

Family/group vs. Periods

Answer 18

18 groups
7 periods
Groups go vertical
Periods go horizantal

Question 19

What are the properties of alkali Metals?

Answer 19

Very reactive
Silvery
Lustrous 
Soft
Low density
Not often on their own

Question 20

What are the properties of alkaline earth metals?

Answer 20

Lustrous
Silvery
Less soft then alkali Metals
Not as reactive

Question 21

What are the properties of halogens?

Answer 21

Very reactive

Often form compounds with alkali Metals

Question 22

What are the properties of noble gases?

Answer 22

Very stable 
Colourless
Odourless
Tasteless
Glow when an electric current is passing through

Question 23

Why are noble gases stable?

Answer 23

They have an orbit ring with 8 electrons which is a full orbit ring.

Question 24

What does the group number tell us?

Answer 24

Elements have:
Similar properties
The number of valence electrons
Reactivity

Question 25

What did Democritus discover?

Answer 25

Matter can be divided until there is a particle so small it is indivisible Atoms are different sizes, in constant motion, and are separated by empty space

Question 26

What did Aristotle propose?

Answer 26

``` There are 4 basic substances Fire Air Earth Water This was accepted for almost 2000 years ```

Question 27

What did John dalton discover? | 1807

Answer 27

``` Daltons atomic theory: All matter is made of tiny particles All atoms of an element are identical Atoms cannot be created or destroyed Can be rearranged to form a new substance Compared the atom to a billiard ball ```

Question 28

What did J.j. Thompson propose? (1897)

Answer 28

``` Compared the atom to raisin bread Bread=positive parts of atom Raisins=negative electrons All atoms are neutral Contain electrons Electrons are evenly distributed ```

Question 29

What did Ernest Rutherford do? (1909)

Answer 29

``` The gold foil experiment Aimed a beam of positively charged particles at a price of gold foil then caught them on a fluorescent screen. Most particles went straight through Some particles were slightly deflected Some particles were greatly deflected. ```

Question 30

What did James Chadwick discover? (1932)

Answer 30

There was a empty space with a tiny dense core called a nucleus Nucleus is made of proton and neutrons Same amount of protons and electrons Planetary model

Question 31

What is the relative mass of subatomic particles?

Answer 31

P=1 N=1 E=0.0005

Question 32

What did Niels Bohr discover? (1913)

Answer 32

Electron shell Determined by studying hydrogen Electrons orbit the nucleus Each electron has a definite amount of energy If they have enough energy they can jump to a different orbit

Question 33

How to balance an chemical equation

Answer 33

1. Count the number of each type of atom on both sides of the reaction arrow. 2. Add a coefficient in from of a chemical formula. Remember, a coefficeint multiplies by everything that comes after it. 3. Check your work.

Question 34

What is an ionic compound?

Answer 34

Compounds formed between metals and non-metals.

Question 35

How many atoms are in a full valence shell?

Answer 35

8

Question 36

What is formed when a metal atom gains or loses electrons?

Answer 36

Positive ions called cations.

Question 37

What is formed when non-metal atoms gain electrons?

Answer 37

Negative ions calf anions.

Question 38

How to draw an ionic compound

Answer 38

1. Write symbols for each element. 2. Create a Lewis structure for each. 3. Draw an arrow (or more if needed) to show the transfer of electrons from the metal to non metal. 4. Redraw the Lewis structures but with the added or removed electrons. The non metal should have a full outer shell. 5. Place square brackets around the ion. 6. Determine the charge for each ion and right it on the top right corner of the brackets.

Question 39

How to write a chemical name.

Answer 39

1. Name the metal directly from the Periodic Table. | 2. Name the non metal second, but change the ending to ‘ide’

Question 40

Steps to writing a chemical formula:

Answer 40

1. Write the symbol of the METAL atom with its charge above it. 2. Write the name of the NON METAL with its charge above it. 3. Criss cross the charges (leave out the signs) 4. Reduce to the lowest terms, if necessary.

Question 41

What are Molecular compounds

Answer 41

Compounds formed between non metals. Non metal atoms interact by sharing electrons so that both get a full valence shell. These atoms are joined by a covent bond.

Question 42

Charges of each group.

Answer 42

``` 1- +1 2- +2 13- +3 14- +/- 4 15- -3 16- -2 17- -1 18- 0, full valence shell ```

Question 43

What are molecular compounds called because of the amount of they’re bonds?

Answer 43

1 pair- single bond 2 pairs- double bond 3 pairs- triple bond

Question 44

Steps to draw a molecular compound

Answer 44

1. Write the symbols for each element. 2. Create the Lewis structure for each. 3. Draw circles to show the sharing of electrons - after sharing, all atoms should have a stable number of valence electrons 4. Draw the bond structure (ball and stick model) using symbols and lines. - use one line for each pair of electrons that is shared.