Patterns in the Periodic Table

Question 1

How are elements arranged in the Periodic Table?

Answer 1

arranged in order of
increasing proton (atomic) numbers

Proton (Atomic) number: no. of protons in the nucleus of an atom
Nucleon (Mass) number: no. of protons & neutrons in the nucleus of an atom

Question 2

How do we classify the Elements in the Periodic Table?

Answer 2

Metals & Non-metals & Metalloids
- Metals on the left and middle
- Non-metals on the right (inclusive of hydrogen)
- Metalloids near dividing line (exhibit both metallic and non-metallic properties)

Question 3

group 1

Answer 3

alkali metals

Question 4

group 17

Answer 4

halogens

Question 5

group 18

Answer 5

noble gases

Question 6

groups 3-11

Answer 6

transition metals

Question 7

how are elements in same grp related

Answer 7

same grp, same no. of valence es, similar chemical properties

metals lose es -> cations
non-metals gain es -> anions

Question 8

group trends (3)

down the group

Answer 8

1. electron shells increase
2. atomic size increase
3. distance of v.e. away from nucleus increase

Question 9

how are elements in same period related

Answer 9

same period, same no. of valence shells

Question 10

period trends (3)

across left to right

Answer 10

1. increase non-metallic properties, decrease metallic properties
2. protons no. increase
3. atomic radius decrease

Question 11

why atoms decrease in size across period

Answer 11

• sheilding effect same (replusion from es in inner shells)
• electrons increase, electrostatic forces of attraction between nucleus and valence electrons increase
• v.e. pulled closer to nucleus, atoms smaller

Question 12

group 1 unique trait

Answer 12

very reactive, found in nature as compounds only

Question 13

grp 1 physical properties

Answer 13

1. soft, can be cut easily
2. low density (increase down)
3. low m.p. + b.p. (decrease down)

Question 17

group 17 unique trait

Answer 17

share one v.e. to form one single covalent bond, diatomic molecules