1 Atomic Structure and the Periodic Table

Question 1

1) All substances are made up of _____.

2) An ____ is the ________ part of an _______ that can exist.

Answer 1

1) atoms

2) atom, smallest, element

Question 2

Compounds are formed from elements by ________ _________.

Answer 2

chemical reactions

Question 3

Chemical reactions always involve what?

Answer 3

The formation of one or more new substances, involving detectable energy change.

Question 4

Complete and balance the equations:
sodium + chlorine →
Na + Cl2 →

Answer 4

→ sodium chloride

2Na + Cl2 → 2NaCl

Question 5

Halogens react with…

Answer 5

both metals and non-metals.

Question 6

Fluorine forms fluoride
Chlorine forms chloride
What are the “ides” called and what is the general term for them?

Answer 6

Salts

General term = halides

Question 7

Define mixture.

Answer 7

Different substances (elements or compounds) not chemically combined, which can be separated by physical processes.

Question 8

Name some physical processes (4).

Answer 8

Filtration
Crystallisation
Distillation
Chromatography

Question 9

Physical processes…

Answer 9

…do not involve chemical reactions and no new substances are made.

Question 10

In their periodic tables, Newlands and Mendeleev arranged the elements in order of ______.
The ______ particle allows the elements to be arranged in order of their ______ ______ in the modern periodic table.

Answer 10

1) weight
2) proton
3) atomic number

Question 11

Explain why the reactivity of elements increases going down Group 1 but decreases going down Group 7.

Answer 11

• As you go down the group, the distance from the outer shell and the nucleus increases (period tells you how many shells)
• Therefore, the attraction between the outer electrons and the nucleus is less as you go down the group
• It is easy for group 1 elements to lose an electron to get a full outer shell, so reactivity increases as you go down group 1
• It is harder for group 7 elements to gain an electron to get a full outer shell, so reactivity decreases as you go down group 7

Question 12

Mass number/Relative atomic mass

Answer 12

Number of 𝗽𝗿𝗼𝘁𝗼𝗻𝘀 + number of 𝗻𝗲𝘂𝘁𝗿𝗼𝗻𝘀

Question 13

Describe the plum pudding model (Marsden).

Answer 13

Negative electrons surrounded by a sea of positive charge.

Question 14

Compare the plum pudding model with the nuclear model of the atom.

Answer 14

𝕎𝕙𝕖𝕟 𝕔𝕠𝕞𝕡𝕒𝕣𝕚𝕟𝕘 𝕤𝕒𝕪 𝕨𝕙𝕒𝕥 𝕚𝕤 𝕥𝕙𝕖 𝕤𝕒𝕞𝕖 𝕒𝕟𝕕 𝕕𝕚𝕗𝕗𝕖𝕣𝕖𝕟𝕥:
• Plum pudding model has electrons embedded in the atom, whilst nuclear model has electrons located around the nucleus
• Plum pudding has no nucleus, nuclear has nucleus in atom
• Plum pudding has no orbitals, whilst nuclear does
• Plum pudding model has mass where electrons are embedded, whilst nuclear model has mass concentrated in nucleus (electrons have no/negligible mass)

Question 15

Why did other chemists refuse to accept Newlands’ Law of Octaves and other ideas?

Answer 15

• Not all the elements fitted the pattern

* They didn’t agree with the fact that Newland placed two atoms into the same box

Question 16

Why are alkanes and hydrocarbons (e.g. CₙH₂ₙ₊₂) not in the periodic table?

Answer 16

They have different elements in them, they are compounds.

Question 17

Group number

Answer 17

Tells you how many 𝗲𝗹𝗲𝗰𝘁𝗿𝗼𝗻𝘀 are on an element’s outer shell.

Question 18

Period number

Answer 18

Tells you how many 𝘀𝗵𝗲𝗹𝗹𝘀 the element has.

Question 19

Explain the reactivity trend in terms of atomic structure.

Answer 19

• As you go down the group there are more shells
• The more shells an elements has, the further away the outer shell is from the nucleus
• This makes it harder to gain an electron, or easier to lose an electron (depending on group number)