the periodic table

Question 1

what does the group that the elements are in tell us about the element?

Answer 1

the number of valence electrons in an atom of that element

Question 2

what does the period that the elements are in tell us about the element?

Answer 2

the number of electron shells/valence shells in an atom of that element

Question 3

does the number of protons increase or decrease across the periodic table?

Answer 3

increase

Question 4

does the number of valence electrons increase or decrease across the table?

Answer 4

increase

Question 5

does the metallic property increase or decrease across the periodic table? why?

Answer 5

decrease
- on the left side of the periodic table, metal atoms tend to lose electrons and form positive charged ions
- moving across the period, there is higher tendency for elements to gain electrons as elements are non-metals and form negative charged ions

Question 6

does the number of protons increase or decrease DOWN the periodic table?

Answer 6

increase

Question 7

does the atomic size/radius increase or decrease DOWN the periodic table?

Answer 7

increase
-number of electron shells increases

Question 8

does the number of valence electrons increase or decrease DOWN the periodic table?

Answer 8

remains the same!

Question 9

are chemical reactions similar or different DOWN the group?

Answer 9

similar as they have the same number of valence electrons

Question 10

what are sub-atomic particles?

Answer 10

protons, neutrons, electrons

Question 11

define isotopes

Answer 11

atoms of the same element having the same number of protons but different number of neutrons

Question 12

why are fluorine, chlorine and iodine placed in the same group?

Answer 12

these elements have 7 valence electrons

Question 13

are elements in group 1 soft or hard

Answer 13

soft, can be cut with a knife
-shiny and silvery but quickly tarnish when cut

Question 14

do elements in group 1 have low or high density?

Answer 14

low density

Question 15

how can we prevent group 1 metals to react with water and oxygen gas?

Answer 15

store in oil

Question 16

does the melting and boiling points increase or decrease down group 1?

Answer 16

decrease

Question 17

does reactivity increase or decrease down group 1?

Answer 17

increase

Question 18

colour and physical state of fluorine at room temperature

Answer 18

yellow, gas

Question 19

colour and physical state of chlorine at room temperature

Answer 19

greenish yellow, gas

Question 20

colour and physical state of bromine at room temperature

Answer 20

reddish brown, liquid

Question 21

colour and physical state of iodine at room temperature

Answer 21

purplish black, solid

Question 22

colour and physical state of astatine at room temperature

Answer 22

black, solid

Question 23

does the density increase or decrease down group VII?

Answer 23

increase

Question 24

does melting and boiling point increase or decrease down group VII?

Answer 24

increase

Question 25

does reactivity increase or decrease down group VII?

Answer 25

decrease

Question 26

use of helium

Answer 26

fill up balloons

Question 27

use of neon

Answer 27

entertainment lights

Question 28

use of argon

Answer 28

provide inert atmosphere welding/ light bulbs

Question 29

why are noble gases unreactive?

Answer 29

atoms of noble gases do not need to lose, gain or share electrons
stable electronic configuration

Question 30

what is formed when aqueous chlorine is added to sodium bromide? why?

Answer 30

a reddish brown solution is formed due to the formation of bromine. chlorine is more reactive than bromine. hence it displaces bromine from sodium bromide

Aqueous chlorine + sodium bromide → sodium chloride +bromine

Question 31

what is formed when aqueous chlorine is added to potassium iodide? why?

Answer 31

a brown solution is formed due to the
formation of iodine. chlorine is more reactive than iodine. hence it displaces iodine from potassium iodide.

Aqueous chlorine + potassium iodide → potassium chloride + iodine

Question 32

what is formed when aqueous chlorine is added to sodium fluoride? why?

Answer 32

no reaction. fluorine is more reactive than chlorine. hence chlorine is unable to displace fluorine from sodium fluoride

Cl2(aq) + 2NaF(aq) → no reaction