C2

Question 1

What were believed to be the 4 basic elements in ancient Greek time?

Answer 1

Earth, Air, Fire and Water

Question 2

Summarise the evolution of the atomic model

Answer 2

Early 19th century - John Dalton - atoms are solid spheres and were made up of different chemical elements
1904 - J J Thompson - atoms are not solid spheres, as they must contain smaller, negatively charged particles - plum pudding model
1911 - Rutherford - there is a small positive centre of mass, with a cloud of negative particles around
Bohr - electrons are in fixed shells

Question 3

When are molecules formed?

Answer 3

When two or more atoms are held together by covalent bonds

Question 4

When are ions formed?

Answer 4

When atoms gain or lose electrons

Question 5

Who made the first proper periodic table?

Answer 5

Mendeleev

Question 6

State 3 characteristics of non-metals

Answer 6

NON METALS-

• Poor conductors
• Dull looking
• Lower density
• Lower MP and BP
• Reactivity decreases as you go down the periodic table
• Form compounds with ionic or covalent bonds

Question 7

State 3 characteristics of metals

Answer 7

METALS-

• Shiny looking
• Great conductors
• Higher density
• Higher MP and BP
• Reactivity increases as you go down the periodic table
• Form compounds with ionic or metallic bonds

Question 8

State 3 characteristics/trends in group 1 elements and why

Answer 8

• They are reactive (only 1 electron so lose it very readily)
• MP and BP decrease as you go down (more shells so further away so weaker attraction to nucleus)
• More reactive as you go down (more shells so further away so less attraction to nucleus so lose electron more readily)

Question 9

State 3 characteristics/trends in group 7 elements (the halogens) and why

Answer 9

• They are reactive (only 1 electron to gain)
• MP and BP increase as you go down (more electrons = greater intermolecular forces)
• Less reactive as you go down (more shells so further away from nucleus so harder to attracted electrons)

Question 10

What are states and colours of the different halogens?

Answer 10

Fluorine = yellow gas
Chlorine = green gas
Bromine = red-brown liquid which gives off orange vapour at room temperature
Iodine = grey solid which gives off purple vapour at room temperature

Question 11

What are group 0 elements called?

Answer 11

Noble gases

Question 12

State 3 characteristics/trends in group 0 elements (the halogens) and why

Answer 12

• Non-reactive (they have a full outer shell so no reason to react so are inert)
• MP and BP increase as you go down (more electrons = greater intermolecular forces)
• Colourless gases at room temperature

Question 13

State the noble gases in order of ascending MP and BP

Answer 13

Helium - Neon - Argon - Krypton - Xenon - Radon

Question 14

What are anions?

Answer 14

Negative ions

Question 15

What are cations?

Answer 15

Positive ions

Question 16

What is an ionic bond?

Answer 16

When a metal and a non-metal react together, and the metal atom loses electron/s to form a positive ion, and the non-metal atom gains electron/s to form a negative ion, and the attraction between a positive and negative ion holds them together

Question 17

What are the general properties of ionic compounds?

Answer 17

• High MP and BP (strong attraction)
• Solid ionic compounds do not conduct, but liquid ones do (solid = fixed in place whereas liquid = free to move)
• Dissolve easily in water (ions separate and are free to move due to their charges)