What is the maximum number of electrons that can be accommodated in the d-subshell?
2
6
10
14
Subshells hold maximum electrons: s = 2, p = 6, d = 10, f = 14.
Which block in the periodic table contains elements with valence electrons entering the s-subshell?
s-block
p-block
d-block
f-block
Groups 1 and 2 belong to the s-block as their outermost electrons enter the s-subshell.
What is the subshell electronic configuration of Sodium (Na, Atomic Number 11)?
1s^2 2s^2 2p^6 3s^1
1s^2 2s^2 2p^5 3s^2
1s^2 2s^2 2p^7
1s^2 2s^4 2p^5
Sodium (Z = 11) subshell electronic configuration: 1s^2 2s^2 2p^6 3s^1.
How is the period number of an element determined from its subshell configuration?
Number of valence electrons
Highest principal quantum number (shell number)
Total number of subshells
Atomic mass
The highest shell number in configuration indicates the period of the element.
What is the group number of an element with outer configuration 3s^2 3p^4?
Group 4
Group 6
Group 14
Group 16
For p-block elements: Group number = 12 + valence p-electrons = 12 + 4 = Group 16.
Which block of elements generally exhibit variable oxidation states?
s-block
p-block
d-block
Noble gases
Transition metals (d-block) exhibit variable oxidation states due to small energy difference between (n-1)d and ns subshells.
What is the oxidation state of Fe in FeCl3?
+1
+2
+3
-3
Chlorine has -1 oxidation state. .
Which subshell has lower energy and is filled before 3d?
3p
4s
4p
3s
According to Aufbau principle, 4s () fills before 3d ().
Elements in Group 18 of the periodic table are known as:
Alkali Metals
Halogens
Noble / Inert Gases
Lanthanides
Group 18 elements have complete octet configuration (ns^2 np^6) and are unreactive noble gases.
What is the noble gas shorthand configuration for Chlorine (Cl, Atomic Number 17)?
[Ne] 3s^2 3p^5
[Ar] 4s^1
[He] 2s^2 2p^6
[Ne] 3s^1 3p^6
Neon core is 10 electrons. .