Science 9 - Chapter 2 Test

Question 0

Isotopic Forms

Answer 0

Atoms or elements may have several isotopic forms. For example, neon has two common forms, one with 10 neutrons and one with 12 neutrons.

Question 1

Isotopes

Answer 1

Atoms that have the same number of protons but have different numbers of neutrons. Because they have the same number of protons they are the same element. Different numbers of neutrons make these different forms of the same element or atom.

Question 2

How to distinguish two different isotopic forms?

Answer 2

To distinguish the two, they are described by their mass numbers. The form with 10 neutrons is described as neon-20. The form with 12 neutrons is described as neon-22. They can also be described in symbol form.

Question 3

Where do electrons exist?

Answer 3

Outside the nucleus , but they have certain levels that they occupy. We call these levels Bohr electron shells, and they are part of a theory called the Bohr Atom. We will only deal with the first 20 atoms (first three Bohr shells) because atoms beyond these require another theory.

Question 4

Maximum number of electrons

Answer 4

Each Bohr shell has a maximum number of electrons
1st shell maximum 2 electrons
2nd shell maximum 8 electrons
3rd shell maximum 8 electrons

Question 5

When are atoms stable?

Answer 5

When they have a filled outer shell. When the valence shell is full the element does not want to gain or lose any electrons and is unreactive. When an element has one less than a full valence shell, it will pull the single excess electron from another element’s valence shell. This results in two stable atoms.

Question 6

Ion || Charge

Answer 6

When an element has one more electron than proton (remember that protons are positively charged and electrons are negatively charged.) This gives it a net charge of -1. This stable species is now called a ion and is written differently.

Question 7

Why is the Periodic table called the Periodic table?

Answer 7

Periodic means to recur regularly. In the periodic table there are certain characteristics that are periodic that is, regularly recurring.

Question 8

Who created the periodic table? When?

Answer 8

Dmitri Mendeleev in 1867

Question 9

5 things periodic table gives for each element

Answer 9

1. atomic number
2. symbol
3. name
4. atomic mass
5. ion charge(s)

Question 10

Ion’s Charge

Answer 10

An electrical charge that forms on an atom when it gains or loses electrons.

Question 11

Ion

Answer 11

electrically charged atom

Question 12

What properties do metals have?

Answer 12

1. solid - except mercury (a liquid)
2. shiny lustre
3. good conductors of heat and electricity
4. malleable
5. ductility

Question 13

What properties do non-metals have?

Answer 13

1. some gases
2. some solids
3. only bromine is a liquid
4. not very shiny
5. poor conductors of heat and electricity
6. brittle
7. not ductile

Question 14

What properties do metalloids have?

Answer 14

1. solids
2. can be shiny or dull
3. may conduct electricity
4. poor conductors of heat
5. brittle
6. not ductile

Question 15

Which side of the staircase are metals found?

Answer 15

left side

Question 16

what are the horizontal rows on the periodic tables called?

Answer 16

periods

Question 17

What do the vertical columns on the periodic table called?

Answer 17

chemical families

Question 18

what do the vertical columns have in common?

Answer 18

similar physical and chemical properties

Question 19

4 well known families

Answer 19

alkali metals
alkaline earth metals
halogens
noble gases

Question 20

Which alkali metal is most reactive?

Answer 20

cesium

Question 21

what 2 substances do alkali metals highly react with?

Answer 21

oxygen and water

Question 22

What ion charge do the alkali metals have

Answer 22

+

Question 23

are alkali earth metals more or less reactive than alkali metals?

Answer 23

less

Question 24

what ion charge do earth metals have?

Answer 24

+22

Question 25

what family are fluorine, chlorine, bromine, and iodine a part of?

Answer 25

halogens

Question 26

what ion charge do halogens have?

Answer 26

-

Question 27

which halogens are gases?

Answer 27

fluorine and chlorine

Question 28

which halogen is least reactive?

Answer 28

iodine

Question 29

what ion charge do noble gases have?

Answer 29

0

Question 30

will any of the noble gases react under normal conditions?

Answer 30

no

Question 31

what are the properties of noble gas at room temperature?

Answer 31

colourless, odourless, gases

Question 32

numbers of particles in an atom

Answer 32

Protons = atomic number
electrons = atomic number (in a neutral atom)
atomic mass = average mass of an element
mass number = protons + neutron*
neutrons = mass number - atomic number

*If you are not told anything else you could make a reasonable guess at a mass number by taking the atomic mass and rounding it to the nearest whole number

Question 33

the nucleus

Answer 33

1. is tiny
2. is positively charged (all protons are in the nucleus)
3. has most of the mass of an atom (protons & neutrons)
4. protons and neutrons cannot be easily removed

Question 34

electrons

Answer 34

1. exist in shells outside the nucleus
2. electron shell is negatively charged (contains only electrons)
3. occupies most of the volume of an atom
4. same number as protons if the atom is neutral (could differ if atom is charged)

Question 35

what makes an ion charged?

Answer 35

number of electrons it gains or loses

Question 36

rutherford’s model

Answer 36

Ernest Rutherford’s gold foil experiment led him to propose a nuclear atom, where there was a heavy nucleus in the center, with the electrons occupying the outer areas of the atom.