C2:Periodic Table

Question 1

How were elements classified in the early 1800s?

Answer 1

• By their atomic weight

- By their physical and chemical properties.

Question 2

Describe two changes Mendeleev made to early periodic tables…

Answer 2

• In 1869 he ordered elements in terms of similar properties

- He predicted properties of undiscovered elements,like germanium.

Question 3

What are the trends of group 1 and group 7?

Answer 3

• group 1 elements react more virgorously as you go down.

- group 7 elements reactivity decreases as you go down the groups.

Question 4

Using periodic table,state how many electrons beryllium has in its outer shell…

Answer 4

-2 electrons

Question 5

Why would chlorine react similarly to bromine?

Answer 5

-Because they are in the same group es eachother.

Question 6

Suggest what ions potassium forms,if for example Sodium forms 1+ ioms.

Answer 6

-K+ Ions

Question 7

What do metal elements form when they react?

Answer 7

• positive ions

- (non metals dont form positive ions)

Question 8

Iodine generally reacts by forming negative ions,is iodine a metal or a non metal?

Answer 8

-Iodine is a non-metal

Question 9

What are some properties of metals?

Answer 9

• They are strong,but can be malleable.
• They are great at conducting heat and electricity.
• They have high boiling and melting points.

Question 10

State whether metals generally form poitive ions or negative ions.
Explain why they form these ions with reference to position in periodic table.

Answer 10

• Metals generally form positive ions
• Metals to the left of the periodic table dont have many electrons to remove.
• Metals at the bottom of the table have outer electrons which are far from nucleus so feel a weaker attraction.
• Meaning not much energy is needed to remove electrons so its feasible for the elements to react to form positive ions.

Question 11

What happens when Group 1 metals are put in water?

Answer 11

• They react vigorously,the more down the group the greater reaction
• Hydrogen is produced for potassium and below in the group
• Hydroxides are formed that dissolve in water to give alkaline solutions.

Question 12

Write a word equation for the reaction between lithium and water…

Answer 12

Lithium + Water –> lithium hydroxide + hydrogen

Question 13

What do the trends for Group 1 as you go down include?

Answer 13

• Increase in reactivity
• Lower melting and boiling points
• Higher relative atomic mass

Question 14

As you go down group 7 the halogens….

Answer 14

• become less reactive
• have higher melting and boiling points
• have higher relative atomic masses

Question 15

Why do Group 7 elements get less reactive as you go down the group?

Answer 15

-Because its harder to gain an extra electron,because the outer shell is further from the nucleus.

Question 16

What occurs when Halogens bond with Metals

Non metals with Metals

Answer 16

• The halogens from 1- ions called Halides (F-,Cl-,Br- and I-),for example Na+Cl-.
• These compound have ionic structures were for example Na would lose an electron(dot) and join Cl (with crosses).

Question 17

How can a displacement reaction occur?

Answer 17

-When a more reactive halogen and the salt of a less reactive one react together.
%
-e.g chlorine can displace bromine and iodine from an aqueos solution of its salt (a bromide or iodide)

Question 18

What are some features of Noble Gases (Group 0) …

Answer 18

• They are inert,meaning they are stable and dont react very much.
• They exist as monoatomic gases-single atoms not bonded to each other
• They are non-flammable
• They all have eight electrons in thr outer energy level,apart from helium which has two.

Question 19

What are some patterns in the properties of the Noble Gases?

Answer 19

-The boiling points of the noble gases increase as you move down the group along with increasing relative atomic mass.

Question 20

Why does boiling point increase in Group 0 as you move down?

Answer 20

-Due to an increase in the number of electrons in each atom leading to greater intermolecular forces between them,needing to be overcome.

Question 21

Radon and Krypton have boiling points of -62 °C and -153 °C

Predict the boiling point of xenon…

Answer 21

-Xenon comes in between radon and krypton,so boiling point woukd be halfway between their boiling points
-(-152) + (-62) = -215
-215/2 = 107.5 = 108°C
Xenon boiling point around 108°C

Question 22

Does Xenon or Neon have a higher boiling point?

Answer 22

-xenon has a higher boiling point