6 PERIODIC TRENDS

Question 1

what is the period table

Answer 1

list of elements arranged in order of increasing proton (atomic) numbers.

Question 2

how many periods and groups are in the pt

Answer 2

7 periods and 18 groups of elements.

Question 3

what is Elements from Group 3 to 12 are known as

Answer 3

Elements from Group 3 to 12 are known as transition metals or transition metals

Question 4

what doe sthe group represent

Answer 4

number of valence electrons

Question 5

what doe sthe period represent

Answer 5

number of principal quantum shells

Question 6

how to identify metals and non metals on the pt

Answer 6

Step-like line from the top of Group 13 to the bottom of Group 16 divides the elements into metals and non-metals.

Question 7

what oxides do metals form

Answer 7

Metals form basic oxides.

Question 8

what oxides do non-metals form

Answer 8

Non-metals form acidic oxides.

Question 8

what oxides do metalloids form

Answer 8

Metalloids form amphoteric oxides.

Question 9

Similarity within the same Group

Answer 9

Elements in the Group:
- Have the same number of valence electrons
- Have the same chemical properties
- Forms ions with the same charges
- Form compounds with similar formulae

Question 10

properties of elements Down the Group

Answer 10

Down the Group
- Atomic size increase
- Number of principal quantum shells increases
- Reactivity and metallic character increases down a group of metals

Question 11

what are alkali metals

Answer 11

group 1 elements

Question 12

Physical Properties of Alkali Metals

Answer 12

• Relatively soft and can be cut easily with a knife.
• Low melting and boiling points (compared to other metals).
• Good conductors of heat and electricity.

Question 13

Change in Physical properties Down the Group (G1):

Answer 13

• _M_elting points and boiling points decrease down the group.
• _A_tomic radii of Group 1 metals increase down the group.
• _D_ensity of alkali metal increases down the group.
  MAD

Question 14

why does Atomic radii of Group 1 metals increase down the group. and its link to shielding effect

Answer 14

Each Group 1 metal has an increase of 1 core electron shell, hence the shielding effect increases down the group

Question 15

whats a nuclear charge

Answer 15

The protons in the nucleus exert an attractive force on the negatively charged electrons.
its number is the same as proton/atomic number

Question 16

whats the shielding effect:

Answer 16

basically more core shells mean more INNER ELECTRONS, the OUTER ELECTRONS in the outer shells will have a weaker nuclear attraction

Question 17

y is Group 1 are more reactive

Answer 17

they lose their valence electron more easily cuz atomic radii increases by 1 core electron shell -> valence electrons become** further** from the nucleus -> shielding effect increase -> it increases more than the nuclear charge -> effective nuclear charge decreases -> electrostatic forces of attraction between the nucleus and the valence electron becomes weaker. Less energy is required to remove

Question 18

y does Density of alkali metal increase down the group.

Answer 18

the atomic mass(proton number) increases faster than the atomic volume.(no. of shells)

Question 19

what g1s r less dense or more dense than water

Answer 19

Less dense than water: Li, Na and K
Denser than water: Rb and Cs

Question 20

y does Melting points and boiling points decrease down the group.

Answer 20

• Size of metal cation increases down the group.
• Electrostatic forces of attraction between sea of delocalised electrons and metal cations decreases.
• Metallic bonding weakens down the group, less energy required to break the weaker metallic bonds,

Question 21

Chemical Properties of alkali metals

Answer 21

• Group 1 elements are the most reactive metals in the Periodic Table.
• They have similar chemical properties because all the elements have similar electronic configuration, that is, one electron in their outermost shell.
• The Group I metals are very reactive. They react rapidly with air and vigorously with water. They are kept under oil to prevent them from coming into contact with air and water.
• They are called alkali metals as they react readily with water to form alkalis.

Question 22

what happens when grp 1 mix w cold water

Answer 22

All the alkali metals react with cold water to form alkalis (soluble metal hydroxides) and hydrogen gas.

Question 23

grp 1 low density metals showing a trend in melting point

Answer 23

as density increases, melting and boiling points tend to decrease.
(idk if need memorise all the numbers but this the trend other than potasssium)

Question 24

reaction of water + Li

Answer 24

Reacts quickly with cold water.
Li floats on the water.
No flame is seen.
Effervescence is produced.

Question 25

reaction of water + K

Answer 25

Reacts violently with cold water.
K melts and burns with a lilac flame and explodes.
Effervescence is produced.

Question 25

reaction of water + Na

Answer 25

Reacts very quickly with cold water.
Na melts and burns with a yellow flame.
The molten sodium darts around the surface of the water.
Effervescence is produced.

Question 26

what are halogens

Answer 26

grp 17