Unit 2 Notes 1

Question 1

Believed matter consisted of elements

Answer 1

1. earth
2. air
3. fire
4. water

Question 2

Alchemy (13th - 18th centuries)

Answer 2

Even though alchemists did not know about or discorer any parts parts of the atom they are a very important group of people
What was their main goal?
Turning Lead into gold and finding the elixir of life

Question 3

John Dalton -Early 1800s

Answer 3

• proposed the idea the atom was the smallest particle of matter
• English school teacher
• the atom was an indivisible sphere with uniform density
  -atoms of the same element had the same mass and properties
• COULD NOT EXPLAIN BONDING
• known as the Billiard ball model

Question 4

Sir William Crookes (1890s)

Answer 4

• theorized the existence of electrons
• cathode ray tube experiments

Question 5

J.J. Thomson

Answer 5

• 1903 proved the existence of +ve particles known as protons and believed atoms consisted of electrons (-ve) and protons (+ve)
  -he thought the protons gave the atom mass while the elections held the atom together
• 1897 refined cathode ray tube and proved the electron existed.
• known as the Plum Pudding model

Question 6

Becquerel (1896)

Answer 6

• accidentally discovered radioactivity

Question 7

Rutherford (1911)

Answer 7

-discovered the protons were in the center of the atom called the nucleus
-electrons rotated around the center
- most of the mass was located in the nucleus
- known as the Planetary Model

Question 8

James Chadwick (1932)

Answer 8

-discovered the neutron
-believed the neutron was in the nucleus and provided mass to
the atom
- known as the modified planetary model

Question 9

Scientists knew early on that they needed to organize their world
ie the elements and other scientific data. As a result a number ot periodic tables” were developed. However it wasn’t until the 186.05 that a useful periodic table was created

Question 10

Dmitri Mendeleev

Answer 10

• a Russian scientist developed the figst useful periodic table
  -he organized the table by chemical properties and increasing atomic mass
• his table had blank spaces unlike the table of to day
• known as the “Father of the Periodic Table”

Question 11

Why did Mendeleev leave spaces throughout his table?

Answer 11

There were elements that weren’t discovered yet. He used his periodic table to predict the properties of these missing elements.

Question 12

The Periodic Law

Answer 12

The properties of the elements occur periodically when the elements are arranged in increasing order by their atomic numbers.

Question 13

Periodic Table can be divided into rows in columns
There are 4 rows on the Periodic Table known as series or periods.
There are 18 columns on the periodic table known as groups or families

Question 14

Group 1- The Alkali metals

Answer 14

-very reactive.
- become more reactive and metallic down the group
- 1 valence electron -electron in the outer shell
- Li, Ne, K, Rb, Cs, Fr

Question 15

Group 2- Alkaline Earth Metals

Answer 15

-reactive metals
- more reactive and metallic down the group
- 2 valence electrons
- Be, Mg, Ca, Sr, Ba, Ra

Question 16

Group 16 - Chalcogens

Answer 16

-reactive non metals
-Less reactivee and more metallic down the group
-6 valence electrons.
- O, S, Se, Te, Po, Uuh

Question 17

Group 17- Halogens

Answer 17

• very reactive non metals
• less reactive and more metallic down the group
  -7 valence electrons
• diatomic
• F, CI, Br, I, At , Uus

Question 18

Group 18 - Noble Gases

Answer 18

• inert gases /very stable
• do not react under normal conditions
• 8 valence electrons
• не, Ne, Ar, Kr, xe, Rn, Uuo

Question 19

Groups 3-12- Transitional
Metals

Answer 19

-form brightly coloured compounds.
-or 2 valence electrons

Question 20

Non-Metals

Answer 20

•located to the right of the staircase
• brittle nonconductors

Question 21

Metals

Answer 21

• located to the left of the staircase
• conduct electricity
• malleable

Question 22

Metalloids

Answer 22

-elements located along the staircase
- have characteristics of both metals and non-metals (don’t heat up when conducting electricity!