atoms, elements and compounds 1

Question 1

Define element

Answer 1

a substance made of only one type of atom

Question 2

how many elements are there?

Answer 2

118

Question 3

define compound

Answer 3

2 or more elements chemically combined in a fixed ratio

Question 4

define mixture

Answer 4

2 or more elements and/or compound not chemically combined

Question 5

define relative atomic mass

Answer 5

mass of isotopes according to natural abundance

Question 6

Examples of relative atomic mass

Answer 6

Copper 63.5

Question 7

example of isotopes

Answer 7

Chlorine 35 and 37

Question 8

how do you work out relative mass?
(word equation)
(say ‘a’ is atomic mass and ‘n’ is natural abundance)

Answer 8

( a1 × n1)/100 + (a2 × n2)/100

Question 9

relative mass and charge of electron

Answer 9

1/1837 -> relative mass
-1 -> relative charge

Question 10

relative mass and charge of neutron

Answer 10

0 -> relative charge
1 -> relative mass

Question 11

relative mass and charge of proton

Answer 11

1 -> relative mass
+1 -> charge

Question 12

how many electrons on inner, 2nd and 3rd shell?

Answer 12

1 -> 2 electrons
2 and 3 -> 8 electrons

Question 13

mass number (what)

Answer 13

nucleus - protons + neutrons

Question 14

atomic number (what)

Answer 14

protons and electrons

Question 15

democritus discovery:

Answer 15

atomos (greek indivisible) smallest thing everything is made up from

Question 16

jd (who) discovery

Answer 16

John Dalton
atoms = tiny, invisible, solid balls
compounds = different types
elements = same type

Question 17

who and how discovered electrons and how did they thing they were arranged ?

Answer 17

JJ Thompson, cathode Ray, plum pudding model

Question 18

how and who disproved the plum pudding model?

Answer 18

Ernest Rutherford, gold foil experiment using alpha rays, the nucleus is positive

Question 19

who discovered neutrons and their charge?

Answer 19

James Cadwick

Question 20

how many electron in neutral atom?

Answer 20

same as protons

Question 21

define isotope

Answer 21

type of aton with unstable number of neutrons, varient of element

Question 22

why do atoms contain an equal number of protons and electrons, and what are they called if they don’t
?

Answer 22

So atoms have a neutral charge (balance out), if they are not neutral they are called ions

Question 23

how is the periodic table arranged?

Answer 23

Arrangement of the elements in order of atomic number

Question 24

define group and give examples

Answer 24

The columns of the periodic table are called groups. Members of the same group in the table have the same number of electrons in the outermost shells of their atoms : alkali metals, alkali earth metals, halogens, noble gases

Question 25

define period

Answer 25

a row of chemical elements. All elements in a row have the same number of electron shells. Each next element in a period has one more proton and is less metallic than its predecessor