atoms + elements + compounds

Question 1

elements

Answer 1

• pure
• one type of atom

Question 2

compound

Answer 2

• not pure
• more than one element chemically combined

Question 3

mixtures

Answer 3

two or more substances physically combined

Question 4

atom structure

Answer 4

central nucleus containing protons + neutrons surrounded by shells of electrons

Question 5

electron mass

Answer 5

1/1836

Question 6

proton/atomic number

Answer 6

number of protons in the nucleus of an atom

Question 7

mass/nucleon number

Answer 7

total number of protons and neutrons in the nucleus of an atom

Question 8

noble gases have

Answer 8

full outer shell

Question 9

group number

Answer 9

number of outer shell electrons

Question 10

period number

Answer 10

number of occupied shells

Question 11

isotopes

Answer 11

different atoms of the same element with same number of protons but different number of neutrons

Question 12

isotopes have same chemical properties because

Answer 12

they have same number of electrons so same electronic configuration

Question 13

how to calculate Ar from abundances

Answer 13

add all the (mass * abundance)

Question 14

ionic bond

Answer 14

strong electrostatic force of attraction between oppositely charged ions

Question 15

ionic properties

Answer 15

• high m.p and b.p (break very strong forces)
• conduct when molten/aq not solid
  (free mobile ions)

Question 16

ionic lattice

Answer 16

regular arrangement of alternating positive and negative ions

Question 17

covalent bond

Answer 17

formed when a pair of electrons is shared between two (non-metal) atoms leading to noble gas electronic configuration

Question 18

covalent properties

Answer 18

• low m.p and b.p (weak intermolecular forces)
• poor electrical conductivity (no free mobile ions)

Question 19

diamond

Answer 19

• giant covalent
• tetrahedral
• all 4 bonded

Question 20

graphite

Answer 20

• giant covalent
• layers with weak forces (vanderwaals)
• 1 free electron

Question 21

graphite uses

Answer 21

• lubricant (layers slide)
• electrode (free electrons)

Question 22

diamond use

Answer 22

cutting tools (very hard)

Question 23

silicon (IV) oxide

Answer 23

similar properties to diamond because same tetrahedral structure

Question 24

metallic bonding

Answer 24

electrostatic attraction between the positive ions in a giant metallic lattice and sea of delocalized electrons

Question 25

metal properties

Answer 25

- good conductor (mobile electrons) - malleable + ductile (layers slide without bonds breaking)