atomic structure and the periodic table

Question 1

proton number/atomic number

Answer 1

number of protons in the nucleus of an atom

Question 2

nucleon number/mass number

Answer 2

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

Question 3

periods (rows)

Answer 3

indicate the number of energy levels in an atom of the element

Question 4

groups (columns)

Answer 4

indicate the number of outer shell electrons

Question 5

what are isotopes

Answer 5

• atoms of the same element which have the same proton number but a different nucleon number
• similar chemical properties due to same valence
• same protons/neutrons but different neutrons
• different physical properties due to different mass

Question 6

radioactive isotopes

Answer 6

• isotopes can be radioactive or stable
• if they have extra neutrons they may become unstable
• used for cancer treatment, maintaing thickness of material

Question 7

noble gases

Answer 7

• unreactive

- full outer shells

Question 8

alloys

Answer 8

• contains atoms of different sizes
• harder/stronger
• resistant to corrosion more

Question 9

ions

Answer 9

ions are charged particles obtained by the loss or gain of electrons

Question 10

metal ions

Answer 10

• cations

- lose electrons and become positvely charged

Question 11

nonmetal ions

Answer 11

• anions

- gain electrons and become negatively charged

Question 12

when a group 1 metal forms a compound with a group 7 element

Answer 12

• ionic bond formed
• metal atom donates 1 electron to nonmetal atom
• both become stable and form ions

Question 13

ion forces

Answer 13

ions are held together by the electrostatic forces of atraction between them

Question 14

structure of ionic compounds

Answer 14

• giant lattice with crystalline sturcture

- regualr arrangement of alternating positive and negatively charged ions

Question 15

properties of ionic compounds

Answer 15

• high melting and boiling points
• often solid at room temperature
• soluble in water (ion dissociation)
• do not conduct electricity when in solid from but do in aqueous or molten form
• not volatile

Question 16

covalent bond

Answer 16

formsbetween nonmetal and nonmetal

Question 17

properties of covalent bond

Answer 17

• low melting and boiling points
• liquids or gases at room temp
• usually volatile with aromas
• insoluble in water but soluble in organic solvents
• cannot conduct electricity
• low melting and boiling point due to weak intermolecular forces

Question 18

what are examples of

giant covalent structures/macromolecules

Answer 18

diamond and graphite (allotropes of carbon)

Question 19

diamond characterisitcs

Answer 19

• each carbon atom bonded to four other carbon atoms
• tetrahedral structure
• strong covalent bonds but weak intermolecular forces of attraction
• used in jewellry and cutting tools due to hard nature and high melting point

Question 20

diamond properties

Answer 20

• extremley hard and dense
• does not conduct electricity
• very high melting point

Question 21

graphite characterisitics

Answer 21

• each carbon atom bonded to three other carbon atoms
• form hexagonal shaped layers with weak intermolecular forces between the layers which allow them to slide over each other
• free delocalized electrons between the layers
• used as conductors and electrodes for electrolysis because they conduct electricity
• used in pencil lead and lubricators because it is soft and slippery

Question 22

graphite properites

Answer 22

• soft and slippery because layers can slide over each other
• high melting point
• conducts electricity due to presence of free electrons

Question 23

silicon oxide characteristics

Answer 23

• each silicon atom bonded to 4 oxygen atoms while each oxygen atom bonded to 2 silicon atoms
• tetrahedral structure
• strong covalent bonds
• cheap and naturally available as sand

Question 24

metallic bonding

Answer 24

strong electrostatic force of attraction between positive metal ions and delocalised electrons resulting in a giant metallic structure which consists of a regular arrangement of positive metal ions in a sea of free electrons

Question 25

properties of metal due to bonding

Answer 25

• high melting and boiling point
• malleable and ductile
• conductors of electricity