Unit 1 - core questions

Question 1

define atom

Answer 1

the smallest part of an element that can still be recognised as part of that element

Question 2

define element

Answer 2

a substance made of only one type of atom

Question 3

define molecule

Answer 3

a substance made of more than one atom chemically bonded together (can be atoms of the same type)

Question 4

define compound

Answer 4

a substance made of two or more different atoms chemically bonded together

Question 5

define mixture

Answer 5

a substance made of more than one thing not chemically bonded together

Question 6

state the three subatomic particles, their masses, and relative charges

Answer 6

protons neutrons electrons, 1 1 almost 0, +1 0 -1

Question 7

What did rutherfords alpha scattering experiment prove?

Answer 7

atoms have a small dense nucleus with a positive charge

Question 8

how did Bohr adapt the model of the atom?

Answer 8

he said the electrons orbit the nucleus at specific distances

Question 9

what did Chadwick’s work give evidence of?

Answer 9

That the nucleus also contained neutrons as well as protons

Question 10

What is the atomic number of an atom?

Answer 10

the number of protons in an atom

Question 11

what is the mass number of an atom?

Answer 11

the number of protons + neutrons in an atom

Question 12

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

Answer 12

mass number - atomic number

Question 13

how were elements arranged in the early attempts of the periodic table?

Answer 13

by atomic weight

Question 14

how are elements arranged in the periodic table?

Answer 14

by atomic number

Question 15

what do you know about elements in the same group?

Answer 15

they have similar properties (reactions) as they have the same number of electrons in the outer shell

Question 16

why did Mendeleev swap the order of some elements?

Answer 16

so they were in the same group as the elements they had similar properties to

Question 17

why did Mendeleev leave gaps in his periodic table?

Answer 17

for undiscovered elements

Question 18

what is an ion?

Answer 18

an atom that has lost or gained electrons so now has a charge

Question 19

how can solids be separated from liquids?

Answer 19

filtration

Question 20

what is crystallization?

Answer 20

when a solution is heated until crystals start to form, then left to cool until all the water evaporates

Question 21

what does distillation do?

Answer 21

separates a mixture of liquids with different boiling points

Question 22

what decides what element an atom is?

Answer 22

the number of protons

Question 23

why do atoms have no charge?

Answer 23

they have the same number of protons and electrons

Question 24

what is the approximate radius of an atom?

Answer 24

0.1nm (1x10^-14m)

Question 25

how big is the radius of the nucleus compared to that of the atom?

Answer 25

1/10000 the size (so 1x10^-14m)

Question 26

what is an isotope?

Answer 26

an atom with the same number of protons but a different number of neutrons

Question 27

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

Answer 27

multiply the isotope mass by the abundance for each isotope, add them together and divide by 100

Question 28

what type of ions do metals form?

Answer 28

positive ions

Question 29

what type of ions do non-metals form?

Answer 29

negative ions

Question 30

define inert:

Answer 30

unreactive

Question 31

what is a trend?

Answer 31

a pattern in properties

Question 32

state the trend in the melting points of the alkali metals

Answer 32

gets lower down the group

Question 33

what is a displacement reaction?

Answer 33

a reaction in which a more reactive element takes the place of a less reactive element in a compound

Question 34

what are the common properties of transition metals?

Answer 34

-many transition elements have ions with different charges
-form coloured compounds
-are useful as catalysts

Question 35

name some common transition metals:

Answer 35

-chromium
-manganese
-iron
-cobalt
-nickle
-copper