Elements and the Periodic Table

Question 1

How did they organise the periodic table in the 1800s? (2)
What did they not know about?
So how was the name found?

Answer 1

1. By the physical and chemical properties
2. Their relative atomic mass
   Atomic structure of protons and electrons so there were no atomic numbers
   When ordered by relative atomic mass they found that there was a periodic pattern in the properties.

Question 2

What did who find in 1864?
What did he do and what were these called?
But what?
So what happened?

Answer 2

Newlands noticed that every 8th element had similar properties so he listed them in rows of seven.
Newlands’ octaves, the pattern broke down after 3 rows because of the transitional metals, he left no gaps so his work was ignored.

Question 3

So what were the three problems with Newlands’ octaves?

Answer 3

1. His groups contained elements that didn’t have similar properties
2. He mixed up metals and non metals
3. He didn’t leave any gaps for undiscovered elements

Question 4

What did Dmitri Mendeleev do for his table?

Answer 4

He left gaps and predicted new elements

Question 5

How did Mendeleev order his table?

What was the biggest …?

Answer 5

He put the elements in order of atomic mass but he left gaps to keep elements with similar properties in the same vertical columns (groups)
Gap, on the first two rows and between the second and third group.

Question 6

Why were Mendeleev’s gaps clever?

Answer 6

They predicted the properties of the undiscovered elements and it worked when they were discovered

Question 7

What was the reason scientists didn’t think the table was important?
So what changed when Mendeleev did his?
So then …
The in the late 19th century they discovered …….
And the periodic table …..
What is it now accepted as?

Answer 7

When it was released it wasn’t taken seriously, as there wasn’t much evidence to suggest elements did really fit together like that
The newly discovered elements fitted into his gaps, convincing evidence
Scientists realised it was a useful tool for predicting properties of elements
protons and neutrons and electrons
matched up to what had been discovered about the structure of the atom .
A useful summary of the structure of atoms.

Question 8

What happened when subatomic particles were discovered? (2)

Answer 8

The table was arranged in order of atomic number and elements were put into groups

Question 9

How are elements in the PT arranged? So you can predict what?
How are electrons set out in an atom?

Answer 9

By electronic structure
Their chemical properties
In shells corresponding to an energy level

Question 10

What is the group number equal to?

Answer 10

The number of electrons in the highest energy level

Question 11

How are electrons held in place?

The further the electrons are from the nucleus….

Answer 11

By the the positive charge of the protons in the nucleus

The weaker the attraction

Question 12

What is shielding?

Answer 12

When lots of the inner electrons get in the way of the nuclear charge attracting the far out electrons to the nucleus. The attraction of the nucleus is less is there are more inner electrons.

Question 13

What makes far out electrons easily lost? (2)
Meaning the electrons on the far out energy level are … because there’s less …. ….. them in …. .
That’s why group … metals get …. reactive … down the group.

Answer 13

Increased distance, Increased shielding
more easily lost, less attraction holding them in place
1, more, further

Question 14

What does the shielding do when an atom wants to gain an electron?
So group … elements get … reactive as you go down the list.

Answer 14

It means the higher energy level is less likely to gain an electron as there’s less attraction from the nucleus
7, less

Question 15

Describe 3 properties or measures surrounding the group 1 metals…
What is the group called?

Answer 15

1. They are silvery solids
2. Have to be stored in oil
3. Handled with forceps as they burn the skin
   The Alkali metals

Question 16

As you go down the alkali metal group the elements:
become ……. reactive. Why?
have ……. melting and boiling points
The metals have a …. density and the first three are ….

Answer 16

more, the outer electron is more easily lost because it’s further from the nucleus = shielding
lower
low, less dense than water

Question 17

What are the first three elements in group 1?
How many outer electrons do they have….
What does this do?

Answer 17

Lithium sodium and potassium
1
Makes them all very reactive and gives them similar propreties

Question 18

What do the alkali metals do with non-metals?
What are they so keen to do?
What do the made substances look like, that do what?

Answer 18

Form ionic compounds
Lose their one extra outer electron to become a 1+ ion and not share one to become covalent
White compounds, dissolve in water into a colourless solution

Question 19

How do the first 3 group 1 metals react in water?
What’s produced? How do you detect this?
What doe potassium do?
So what is formed in the water?

Answer 19

Very vigorously, they float around and fizz furiously
Hydrogen, a lit splint will squeak as the H2 is ignited
get’s hot enough to light the potassium
… hydroxides that dissolve in water to give alkaline solutions

Question 20

What is the equation for sodium + water? word then symbol…

Answer 20

Sodium hydroxide + hydrogen

2Na (2) + 2H20 (l) = 2NaOH (aq) + H2 (g)

Question 21

What are the group 7 elements called?

What are they?

Answer 21

Halogens

Non-metals with coloured vapours

Question 22

As you go down the halogen group the elements:
become ……. reactive. Why?
have ……. melting and boiling points

Answer 22

less reactive, it’s harder to gain electrons because the outer shell is further from the nucleus = shielding
high

Question 23

Fluorine is how reactive and what type of gas?

Answer 23

Very reactive, poisonous yellow

Question 24

Chlorine is how reactive and what type of gas?

Answer 24

Fairly reactive, poisonous dense green gas

Question 25

Bromine is how reactive and what type of substance?

Answer 25

Dense, poisonous, volatile red-brown liquid

Question 26

Iodine is one of what two types of substance?

Answer 26

Dark grey crystalline solid or purple vapor.

Question 27

How do the halogen atoms exist?

Answer 27

In molecules, a pair of atoms, e.g F2

Question 28

How do the halogens bond? Forming what? (charge, name)

Answer 28

Ionically with metals, to form Halides, 1- ions, Na+F-

Question 29

What can a more reactive halogen do to a less reactive in an aqueous solution of its salt?
For example what will chlorine do in potassium bromide?
What is the equation?

Answer 29

Displace the less reactive halogen from its salt
Displace the bromide to become potassium chloride.
Cl2 + 2KBr = Br2 + 2KCl

Question 30

Where are the transitional metals?

Answer 30

In between group 2 and 3

Question 31

What are the transitional metals’ properties?

1. (electrolysis?)
2. What are they like physically?
3. How reactive are they in comparison to G1?
4. How do their physical properties compare to G1 metals?

Answer 31

1. Good conductors of heat and electricity
2. Dense, strong and shiny
3. Much less reactive and don’t react as vigorously with water or O2
4. Denser, stronger, harder than G1 metals and have much higher melting points than G1 except for mercury

Question 32

Transitional metals have have more than one what?

These often form what?

Answer 32

Ion, Cu+, Cu2+

Different coloured compounds, Fe2+ ions = green compounds, Fe3+ ions = red brown compounds rust

Question 33

Why are transitional metal compounds colourful?

How are they seen in day to day life?

Answer 33

Because of the ion they contain
Gem stones like blue sapphires and green emeralds and colours of pottery glazes depend on transitional metals
Weathered copper is a colourful green

Question 34

Transitional metals and their compounds make what?

An example? (3)

Answer 34

Good catalysts
Iron is the catalyst for the Haber process for ammonia
Magnesium (IV) oxide is a good catalyst for decomposition of hydrogen peroxide
Nickle is used for turning oils into fats for margarine.