Atomis Structure and the Periodic Table Flashcards Preview

AQA GCSE Chemistry > Atomis Structure and the Periodic Table > Flashcards

Flashcards in Atomis Structure and the Periodic Table Deck (23):
1

What does the group number tell you?

how many electrons are in the outer shell

2

What happens if the outer shell is not full

the atom would react to fill it

3

1869, problems Mendeelev overcame

he took 50 known elements and arranged them into his table of elements

4

why did he leave gaps

because the properties of known elements predicted other, as-yet-undiscovered, elements in these locations. This allowed Mendeelev to predict what the properties of the future elements would be.

5

order in which he arranged the periodic table

mostly in atomic mass, but switched that order if it meant the properties meant it should be changed

6

properties of metal

good conductor of electricity
high boiling/melting points
strong, but can be bent

7

atoms normally

gain/share/lose electrons
Metals lose (1+)
Non-metals gain or lose (1-)

8

the further away from the electron means

a weaker attraction

9

In 1800, the only thing Scientists could measure

was the atomic mass because they had not yet discovered proton/electrons to order them in atomic number

10

why was the order of the periodic table wrong in 1800

they placed the elements the wrong way because they were placed in the order of atomic mass

11

Properties of group 1: alkali metals

very reactive - due to the 1 electron in the outer shell
soft and low density

12

group 1 metals must be stored under oil

to keep air and water from reacting with them

13

Group 1 trend

more reactive as it goes down
Higher relative atomic mass
low melting/boiling points

14

Why does group 1 increase in reactivity?

the atoms get larger
the outer electron gets further from the nucleus
the attraction between the nucleus and outer electron gets weaker - so the electron is more easily lost

15

Group 0 properties: Noble gases

colourless gases at room temperature
Monatomic gases-not bonded together
Increase in boiling as you go down

16

Noble gases don't need to lose

or gain any electrons because they have full outer electrons
They dont react with much at all

17

Boiling point of Radon is -62C and krypton -153C. Boiling point of xenon?

(-153) + (-62) = -215
-215 / 2 = -107.5 = 108

18

Colours of Halogens

Flurine = RED (g)
Chlorine = GREEN (g)
Bromine = RED-BROWN (l)
Iodine = PURPLE VAPOUR (s)
States are all at room temp (25C)
Colours get darker as you go down

19

Halogens reactive similarly because

they all have 7 electrons on the outer shell

20

Halogen trend

higher melting points
higher relative atomic mass
Less reactive - harder to gain an extra electron because the outer shell is further from the nucleus

21

More reactive halogens will...
Example

displace all of the other halogens from solutions of their salts, and is displaced by none of the others
*Cl2 + 2KI --> I2 + *2KCl

22

How to find out relative atomic mass:
Cl35 and Cl37 with % of 75% and 25%

(75/100) + 35 = 26.25

(25/100) + 37 = 9.25

26.25 + 9.25 = 35.5

23

Define an isotope

Isotopes are the atoms of an element with different numbers of neutrons. They have the same proton number, but different mass numbers.