Chem Unit 6😭

Question 1

How are elements arranged in the Periodic Table?

Answer 1

• All elements are arranged in order of increasing atomic number.
• Each horizontal row is called a period, each vertical column is called a group.

Question 2

Electron arrangement:
What is a period?

Answer 2

• Atoms of the element in the same period have the same number of shells of electrons
  ( period no= number of occupied electron shell)

Question 3

Electron arrangement:
What is a group?

Answer 3

• Atoms of elements in the same group have the same number of outermost shell electrons
• Eight main groups, Group I to Group VII, followed by Group 0

Question 4

Name the groups:
Group I
Group II
Group VII
Group 0

Answer 4

Group I: alkali metals
Group II: alkaline earth metals
Group VII: halogens
Group 0: noble gases

Question 5

In group 0, ___ has only 2 electrons, the other elements have eight outermost electrons.
___ doesn’t belong in any group.

Answer 5

1. Helium
2. Hydrogen

Question 6

What are the patterns in the periodic table?

Answer 6

-Metals are on the left, nonmetals are on the right, elements near the zigzag line are semi metals.
-Across a period, from left to right, elements change from metal to semi metal to nonmetal.

Question 7

Properties of group I (alkali metals)

Answer 7

-Atoms in the elements have 1 outermost electron.
-All are grey metals
-The metals are soft. We can cut them with a knife.
-Very reactive metals. React vigorously with water, the vigour of reaction increases down the group.
-Stored in paraffin oil
-All react with with nonmetals to form salt. (All white, crystalline and soluble in water)
-Low density

Question 8

Properties of group II (alkaline earth metals)

Answer 8

-All are reactive metals
-All react with non-metals to form salt
-Group II elements are less reactive than group I elements
-Only those lower in the group ( calcium and below ) can react with cold water
-Calcium is stored in a sealed can not parffin oil.
-Reactivity increases, and b.p. and m.p. decreases down the group

Question 9

Properties of group VII ( halogens )

Answer 9

-Halogen atoms have seven outer-shell electrons
-All are toxic/poisonous and smelly
-All react with metals to form salts
-All the halogens are non-metals
-Reactivity decreases, and b.p. and m.p. increases dpwn the group

Question 10

What is the state at room temp. and color of the group VII elements?
Fluorine
Chlorine
Bromine
Iodine

Answer 10

Fluorine: Gas, pale yellow
Chlorine: Gas, greenish-yellow
Bromine: Liquid, reddish-brown
Iodine: Solid, black

Question 11

Properties of group 0

Answer 11

-All are colorless gases at room temp.
-Except helium (duplet structure), all noble gases have eight electrons in the outermost shell (octet structure)
-They are very stable due to their duplet (He) and octet (pther noble gases) arrangement

Question 12

Reactions of group I

Answer 12

1. React with O2
   Metal + oxygen —> Metal oxide
2. React with H2O
   Metal + water —> Metal hydroxide + hydrogen
   Observations: Metals moves on water,Metal burns with Na/K(Golden yellow/lilac)
   Metals melts into ball
3. React with Group VII
   Metal + chlorine —> Metal chloride