Atomic Structure and the Periodic Table

Question 1

structure of an atom

Answer 1

contains a central nucleus that is made up of protons (positively changed) and neutrons (no charge). electrons (negatively charged) surround the nucleus in layers called shells

Question 2

how are the shells arranged

Answer 2

the first shell, closest to the nucleus has 2 electrons. the rest of the shells can hold up to 8 electrons.

Question 3

what determines the group (column)

Answer 3

the number of electrons in the outer shell

Question 4

what determines the period (row)

Answer 4

the amount of shells

Question 5

relative masses and charges

Answer 5

proton - 1m/u and +1
neutron - 1m/u and 0
electron - negligible and -1

Question 6

what is the atomic number

Answer 6

proton number (total number of protons in the nucleus) in periodic table, it is the smaller number

Question 7

what is the mass number

Answer 7

nucleon number (total amount of protons and neutron in nucleus) in periodic table, it is the largest number

Question 8

group 8 (noble gases ) why not reactive

Answer 8

they have a full outer shell, therfore unreactive because they dont have to share electrons

Question 9

what are isotopes

Answer 9

are different atoms of the same element that have the same number of protons but different number of neutrons (mass number changes but atomic stays the same)

Question 10

why do isotopes have the same electronic configuration

Answer 10

because the electron number stays the same therefore chemical properties (reactivity) also stays the same as the proton number does not change

Question 11

what atoms have equal numbers

Answer 11

protons and electrons

Question 12

35 37
C C
17 17

abundances -
75.8% 24.2%

Answer 12

relative atomic mass = 35.5

(75.8x35)+ (24.2x37)
over
100

Question 13

group 1 (alkali metals)

Answer 13

sodium, lithium, potassium (soft metal)
- density increases
- reactivity increases
- melting point decrease

Question 14

when group 1 (alkali metals) react with water

Answer 14

react vigorously, hydrogen bubbles are produced

Question 15

when group 1 (alkali metals) react with oxygen

Answer 15

they burst into flame

Question 16

when group 1 (alkali metals) react with chloride

Answer 16

burst into flame, burn brightly

Question 17

group 7 the halogens

Answer 17

chlorine, bromine, iodine (diatomic non-metals, poisonous, smelly)
-increase density
-decrease reactivity

Question 18

halogens at room temp

Answer 18

fluorine =yellow gas
chlorine = pale green-yellow gas
bromine = red/brown liquid
iodine = grey solid, sublimes to purple
astatine = shiny black solid

Question 19

ions

Answer 19

atoms that have gain or lost electrons therefore now have more or fewer electrons than protons

Question 20

hallide

Answer 20

are halogens, when they react with other substances and become negative ions as they gain electrons

Question 21

displacement reactions

Answer 21

where more reactive element displaces a less reactive element in its compound
sodium + iron chloride –> sodium chloride + iron

Question 22

transition metals

Answer 22

high densities
high melting points
act as catalysts
form colored compounds

Question 23

the noble gases

Answer 23

they are colorless, tasteless, odorless and monatomic as they go round as individual atoms