atomic structure and the periodic table - chemistry revision

Question 1

what are some facts about Mendeleev?

Answer 1

• he ordered the elements by atomic weight
• he left gaps for forgotten elements
• he made predictions for elements that had yet to be discovered

Question 2

what are groups in a periodic table?

Answer 2

-groups are are columns in a periodic table
-elements in the same group (column) have similar reactivity and end with the same number in their electronic configuration
group 1 - 2.1, 2.8.1, 2.8.8.1

Question 3

what are periods in a periodic table?

Answer 3

• periods are rows in a periodic table
• they follow a trend in reactivity
• elements in the same period have the same amount of shells
  period 1 - one shell
  period 3 - three shells
  period 7 - seven shells

Question 4

what are facts about toms that john dalton found out?

Answer 4

• he said all matter is made up of invisible particles called atoms
• he said atoms of the same element are similar in mass and shape but differ from atoms of other elements
• atoms cannot be created or destroyed
• atoms join together to form compound atoms (molecules) in simple ratios

Question 5

what is the relative charge of protons, neutrons and electrons?

Answer 5

protons - positive +1
neutrons - neutral 0
electrons - negative -1

Question 6

what is the relative mass of protons, neutrons and electrons?

Answer 6

protons - 1
neutrons - 1
electrons - negligible 1/1835

Question 7

what is the proton’s, neutron’s and electron’s location in the atom?

Answer 7

proton - nucleus
neutron - nucleus
electron - in energy shells surrounding the nucleus

Question 8

what does the top and bottom number on a element on a periodic table?

Answer 8

top - mass number (protons + neutrons)
bottom - atomic number

Question 9

how do yiu calculate the amount of protons, neutrons and electrons from an element on the periodic table?

Answer 9

protons = atomic number
electrons = atomic number
neutrons = mass number - atomic number

Question 10

what are isotopes?

Answer 10

isotopes are atoms of the same element that have the same number of protons and electrons (same atomic number) but different numbers of neutrons (different mass number)

Question 11

how do you calculate the average atomic mass of an isotope?

Answer 11

% of 1st isotope + % of 2nd isotope
x mass of 1st isotope x mass of 2nd isotope
—————————————————————————–
100

Question 12

in electronic configuration, how many electrons can go on each shell

Answer 12

• 2 electrons in the first shell
• up to 8 in the second shell
• up to 8 in the third shell
• up to 18 in the fourth shell

Question 13

what is the electronic configuration of magnesium (Mg) with 12 electrons?

Answer 13

2.8.2

Question 14

how do you calculate relative formula mass?

Answer 14

relative atomic mass + relative atomic mass = relative
formula
mass