2A yellow solid element exists in allotropic forms which is also present in fossil fuels. Indicate the name:
6
C
Carbon
53
I
Iodine
13
Al
Aluminium
16
S
Sulphur
ACarbon
BIodine
CAluminium
DSulphur
3The element having less ionization energy and less value of electron affinity is likely to belong to:
Hint: Consider which group has the lowest tendency to gain electrons and easiest to lose electrons
AGroup 1 (Alkali Metals)
BGroup 13 (Boron Group)
CGroup 16 (Oxygen Group)
DGroup 17 (Halogens)
4Horizontal rows of the periodic table are called:
AGroups
BPeriods
CSeries
DNone of these
51st period of the periodic table consists of elements:
1
H
Hydrogen
Element 1
2
He
Helium
Element 2
A2
B8
C18
D32
6Alkali metals react with halogens to give:
Na
+
Cl
→
NaCl
AHydrides
BNitrides
CHalides
DNone of these
7Group I elements have ……… electrons in valence shell.
3
Li
Lithium
11
Na
Sodium
19
K
Potassium
37
Rb
Rubidium
A1 electron
B2 electrons
C4 electrons
D6 electrons
8Group 3 elements form:
A2+ ions
B3+ ions
C4+ ions
DAll of these
9Atomic radius …… in a period.
Na
Largest
→
Decreases
Cl
Smallest
AIncreases
BRemains same
CDecreases
DNone of these
10Which one of the following halogens has highest electronegativity?
9
F
Fluorine
17
Cl
Chlorine
35
Br
Bromine
53
I
Iodine
AIodine
BChlorine
CFluorine
DBromine
Short Answer Questions 15×2=30
iWhat is the significance of the word “periodic”?
iiWhy are the most electronegative elements present in sixth and seventh groups?
Hint: Consider electron configuration and tendency to gain electrons
iiiSuppose a new element is discovered. Where would you like to accommodate this element in the periodic table? Constructed Response
?
X
New Element
ivWhat is the first element of the periodic table? Will it lose an electron or gain it? Constructed Response
H
vAtomic radii of boron and aluminum are 88 pm and 125 pm respectively, which element is expected to lose electron or electrons easily? Constructed Response
5
B
Boron
88 pm
→
Down Group
13
Al
Aluminium
125 pm
viHow would you find the atomic radius of an atom? Constructed Response
viiDifferentiate between groups and periods.
viiiDefine periodic law.
ixHow elements are arranged in periodic table?
xWhat is lanthanide? To which period do they belong?
xiDefine normal or representative elements.
xiiWhat is atomic radius? Give its units.
xiiiWhat is electronegativity? Which element has highest electronegativity?
9
F
Fluorine
xivWhy electron affinity values decrease from top to bottom in a group?
xvWhich property explains why chemical reactions occur?
Detailed Answer Questions (Answer any 2) 2×5=10
1Why elements arranged in periodic table?
Key Points:
– Classification based on atomic number
– Similar properties in groups
– Predictable trends in periods
– Organization for study and reference
2What is the role of Henry Moseley in periodic table?
Henry Moseley’s Contributions:
1. Discovered relationship between atomic number and X-ray frequency
2. Established atomic number as fundamental property
3. Corrected discrepancies in Mendeleev’s table
4. Modern periodic law: Properties are periodic function of atomic number
3Define Atomic radius. Explain its trend in periodic table.
