atomic structure

Question 1

define an atom.

Answer 1

the smallest particle of a chemical element that can exist.

Question 2

define an element.

Answer 2

a pure substance made of only one kind of atom

Question 3

what is a compound?

Answer 3

a substance made up of atoms of two or more different elements joined by chemical bonds

Question 4

what is the difference between a mixture and compound?

Answer 4

a mixture combination of two or more different substances that are NOT joined by chemical bonds

Question 5

what is a molecule?

Answer 5

a group of atoms bonded together (can be the same type of atom, or different types of atom)- eg CO2, H2O

Question 5

what is the relative mass of a proton?

Answer 5

1

Question 6

what is the relative mass of a neutron?

Answer 6

1

Question 7

what is the relative mass of an electron?

Answer 7

roughly 1/1836- negligible

Question 8

what is the relative charge of a proton?

Answer 8

+1

Question 9

what is the relative charge of a neutron?

Answer 9

0

Question 10

what is the relative charge of an electron?

Answer 10

-1

Question 11

what is the atomic number?

Answer 11

the number of protons in the nucleus of an atom

Question 12

where are each of the subatomic particles found?

Answer 12

protons and neutrons in the nucleus, electrons in shells orbiting the nucleus

Question 13

what is the average radius of an atom?

Answer 13

0.1 nm (1 x 10^-10 m)

Question 14

what is the average radius of the nucleus

Answer 14

10000 times smaller than atom- 1 x 10^-14 m

Question 15

how do you find the number of neutrons in an atom?

Answer 15

mass number - atomic number

Question 16

define isotope

Answer 16

atoms of the same element that have different numbers of neutrons

Question 17

what does the number of electron shells correspond to?

Answer 17

the period (horizontal row) on the periodic table

Question 18

what is a valence electron?

Answer 18

electrons on the outer shell that are involved in reactions

Question 19

what do outer shell electrons correspond to?

Answer 19

group number in periodic table

Question 20

what was john dalton’s theory of atoms?

Answer 20

believed that atoms could not be divided, but were rearranged in chemical reactions

Question 21

what did john newland find?

Answer 21

noticed a repeating pattern every 8 elements and suggested elements were found in ‘octaves’

Question 22

what were elements ordered by historically?

Answer 22

atomic weight

Question 23

what are elements ordered by now?

Answer 23

atomic number (number of protons)

Question 24

what were dmitri mendeleev's ideas?

Answer 24

he ordered elements by atomic weight BUT changed the order/left gaps to keep elements with similar properties in the same column

Question 25

what were the advantages of mendeleev's ideas?

Answer 25

was able to predict properties of elements in the gaps, eg germanium

Question 26

what charge ions do metals form?

Answer 26

positive

Question 27

what charge do non-metals form?

Answer 27

negative

Question 28

what are some properties of metals?

Answer 28

shiny, malleable, ductile, good conductors of heat and electricity

Question 29

what are some properties of non-metals?

Answer 29

dull, brittle, insulators of heat and electricity, liquids and gases at room temperature

Question 30

what is the pH of metal oxides?

Answer 30

acidic

Question 31

what is the pH of non-metal oxides?

Answer 31

alkaline

Question 32

what are in group 0?

Answer 32

noble gases- helium, argon, neon

Question 33

describe the electron structure of group 0 elements

Answer 33

all have full shells of electrons- stable and very unreactive (inert)

Question 34

what are group 0 physical properties?

Answer 34

all colorless gases at room temperature

Question 35

what is the pattern for boiling point of group 0?

Answer 35

boiling point increases going down the group- larger atoms, more IMF, more energy required to overcome

Question 36

what elements are in group 1?

Answer 36

alkali metals- sodium. lithium, potassium

Question 37

what is the pattern for reactivity in group 1?

Answer 37

increases going down the group- one outer shell electron is further from the nucleus so it is less attracted (receives less shielding) so it is easier to lose.

Question 38

metal + water -> ???

Answer 38

metal hydroxide + oxygen

Question 39

what are the group 7 elements known as?

Answer 39

halogens

Question 40

what are diatomic molecules?

Answer 40

molecules of atoms that travel in pairs- hydrogen (H), nitrogen (N), oxygen (O), fluorine (F), chlorine (Cl), bromine (Br), and iodine (I)

Question 41

what is the pattern in boiling and melting points for halogens?

Answer 41

increase going down the group- more IMF

Question 42

what is the reactivity pattern for halogens?

Answer 42

get less reactive- larger atomic radius, more shielding, less nuclear attraction, harder to gain an electron

Question 43

why will sodium chloride + bromine not react?

Answer 43

displacement reaction will NOT occur since chlorine is more reactive than bromine

Question 44

describe chemical and physical properties of transition metals

Answer 44

slow/no reaction with o2, water and halogens hard, high melting points, strong+ dense

Question 45

describe charges on transition metal ions

Answer 45

form positive ions often with the ability to form more than one ion

Question 46

why are transition metals good catalysts?

Answer 46

because they can form more than one ion

Question 47

what makes transition metals special?

Answer 47

they have an incomplete sub-shell as well as an incomplete outer shell, giving them specialised properties eg colors