Atomis Structure and the Periodic Table

Question 1

What does the group number tell you?

Answer 1

how many electrons are in the outer shell

Question 2

What happens if the outer shell is not full

Answer 2

the atom would react to fill it

Question 3

1869, problems Mendeelev overcame

Answer 3

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

Question 4

why did he leave gaps

Answer 4

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.

Question 5

order in which he arranged the periodic table

Answer 5

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

Question 6

properties of metal

Answer 6

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

Question 7

atoms normally

Answer 7

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

Question 8

the further away from the electron means

Answer 8

a weaker attraction

Question 9

In 1800, the only thing Scientists could measure

Answer 9

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

Question 10

why was the order of the periodic table wrong in 1800

Answer 10

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

Question 11

Properties of group 1: alkali metals

Answer 11

very reactive - due to the 1 electron in the outer shell

soft and low density

Question 12

group 1 metals must be stored under oil

Answer 12

to keep air and water from reacting with them

Question 13

Group 1 trend

Answer 13

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

Question 14

Why does group 1 increase in reactivity?

Answer 14

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

Question 15

Group 0 properties: Noble gases

Answer 15

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

Question 16

Noble gases don’t need to lose

Answer 16

or gain any electrons because they have full outer electrons

They dont react with much at all

Question 17

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

Answer 17

(-153) + (-62) = -215

-215 / 2 = -107.5 = 108

Question 18

Colours of Halogens

Answer 18

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

Question 19

Halogens reactive similarly because

Answer 19

they all have 7 electrons on the outer shell

Question 20

Halogen trend

Answer 20

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

Question 21

More reactive halogens will…

Example

Answer 21

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

Question 22

How to find out relative atomic mass:

Cl35 and Cl37 with % of 75% and 25%

Answer 22

(75/100) + 35 = 26.25

(25/100) + 37 = 9.25

26.25 + 9.25 = 35.5

Question 23

Define an isotope

Answer 23

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