Chemistry 9

Question 1

What is chemistry

Answer 1

Study of matter + its interactions

Question 2

Pure substance

Answer 2

One type of particle

Question 3

Mixture

Answer 3

Two or more pure substances (tow or more particles)

Question 4

Mixtures (elements/compounds)

Answer 4

Elements/compounds not chemically combined

Question 5

Compounds

Answer 5

Atoms of two or more elements combined in a definite proportion (cannot be separated by chemical means)

Question 6

Elements

Answer 6

One type of atom and cannot be broken down by chemical means

Question 7

Homogenous mixture

Answer 7

When a mixture is so uniformly mixed you cannot microscopely tell it apart (air, steel)

Question 8

Heterogeneous mixture

Answer 8

When a mixture is not so uniformly distributed, you can see the different parts

Question 9

Chemical properties

Answer 9

Characteristics that describe the ability of matter to react with another substance to form one or more different substances

Question 10

Physical properties

Answer 10

Characteristics that can be observed of measured without changing its chemical identity

Question 11

List at least 3 chemical properties

Answer 11

Combustibility, reactivity with acids, reactivity with oxygen, lack of reaction

Question 12

List at least 3 physical properties

Answer 12

Colour, malleability, texture, viscosity, conductivity, state of matter, melting, boiling point, hardness, solubility

Question 13

Atomic number

Answer 13

Z

Refers to the number of protons in an atom in a particular element

Question 14

Groups

Answer 14

Vertical column of elements (1-18)

Question 15

Periods

Answer 15

Horizontal row of elements (1-7)

Question 16

Atomic mass

Answer 16

Average mass of an atom

Question 17

Properties of Metals (At least 3)

Answer 17

Good conductors of heat/electricity
Malleable
Ductile
Shiny when pure and unreacted
High melting/boiling points
Loose electrons to form + charged ions (cations)

Question 18

Nonmetals (at least 3)

Answer 18

Poor conductors of heat/electricity
Brittle
Low densities
Low melting/boiling points
Non-ductile
Gain electrons (anions)

Question 19

Metalloids (at least 3)

Answer 19

Mostly solid
Can be shiny/dull
May conduct electricity
Poor heat conductors
Brittle, non-ductile

Question 20

Transition metals

Answer 20

Elements from group 3-12 on the periodic table
3 common properties: metal, form colourful compounds and catalysts
Can form ions with different charges

Question 21

Subatomic particles

Answer 21

Positive protons

Negative neutrons

Question 22

Solve for mass number

Answer 22

Sum of protons and neutrons

Question 23

Number of electrons equals…

Answer 23

Number of protons

Question 24

What is an atom called if it gains or looses an electron

Answer 24

An ion

Question 25

Describe a bohr model

Answer 25

Shell 1 = 2 electrons Shell 2 = 8 electrons Shell 3 = 18 electrons [ electrons are arranged in shells around the nucleus - certain # of electrons allowed in each shell ]

Question 26

How do you make a Bohr model of an ion (example: Fluorine)

Answer 26

Fluorine - 9 protons Has more than 4 electrons on the outermost shell (valence) *line* [ *bohr model of fluorine* ] *line* Add one minus because it has to LOOSE the electron to become fluorine again Now called a fluoride anion Outer valence shell must have 8 electrons

Question 27

How do you know if a ion gains or looses

Answer 27

VALENCE SHELL Less than 4 - loose More than 4 - gain Ex. Fluorine would GAIN because it has MORE THAN 4 electrons on the valence shell

Question 28

Metals don't change their name, non-metals do (T/F)

Answer 28

True

Question 29

Diatomic elements

Answer 29

Elements found in groups of two N2, O2, F2, Cl2, I2, Br2 *hockey stick*

Question 30

Group 1 elements: Proterties

Answer 30

Further you go down = more reactive

Question 31

Halogens

Answer 31

Group 17 Non-metals Low melting/boiling points, poor electrical conductors Formerly known as group 7 (7 valence electrons

Question 32

Reactivity: Group 17

Answer 32

Atomic radius increases as it goes down- Wants to grain a valence electron- decrease in reactivity *halogens* Less valence shells at top, increase in reactivity

Question 33

The easier it is to gain/lose an electron.....

Answer 33

The more reactive it is

Question 34

Properties of transition metals

Answer 34

Less reactive than group 1 and 2 | Similarities exist as we move across a period rather than down a group`

Question 35

Inert gases

Answer 35

Noble gases are known as this ebcause they do not react with anything

Question 36

Shielding

Answer 36

The decrease in attraction between an electron and the nucleus in any atom with more than one in electron shell

Question 37

Octet rule

Answer 37

The tendency of an electron to gain a valence shell with a total of 8 electrons

Question 38

Naming simple ionic compounds: Lithium and nitrogen

Answer 38

Name: Lithium nitride Formula: Li 1+, N3- Add three more Li's to balance out the charges = Li3N

Question 39

Anions always change their names (T/F)

Answer 39

True -ide

Question 40

Ionic compounds with multivalent elements

Answer 40

Same as simple ionic compounds, but pay attention to the roman numerals.

Question 41

Polyatomic ions

Answer 41

Same as simple ionic compounds, however, if the polyatomic ion is used more than once put a bracket around Ex. Mg(OH)2

Question 42

Covalent compounds (Ex. Co2 and oxygen difluoride)

Answer 42

Two non-metals Carbon dioxide Di because there are two oxygens OF2

Question 43

Dissociate and associate

Answer 43

D; To dissolve | A: To come together

Question 44

Properties of ionic compounds

Answer 44

``` Conducts electricity when molten Hard High melting point Non-conductor hen solid Brittle ```