Explore topic-wise InterviewSolutions in Current Affairs.

The increasing order of the atomic radii of elements Na, Rb, K, Mg is Na < Mg < K < Rb.

(a) (i) Tendency to lose electrons decreases.
(ii) Increases.
(b) The three compounds are X(NO₃)₂, XSO₄ and X₃(PO₄)₂.
Valence electrons of element X is 2. Therefore, element X belongs to group 2. It will form ionic compounds because X loses 2 electrons to achieve the electronic configuration of inert gas and forms a positively,charged ion.

(A) The electronic configuration of Mn⁺² is 2, 8, 13.

The answer is (d) F, O, N

Atomic radius increase as move from left to right across a period. N(7), O(8) and F(10) are in increasing order of atomic numbers.

The tendency to lose electrons will decrease across a period as the effective nuclear charge acting on the valence shell electrons increases.

The answer is (b) F

• Sodium has 1, magnesium has 2 and Aluminium has 3 electron in its outermost shell whereas Fluorine has 7 electron in its outermost shell.
• Hence Fluorine does not lose electron easily.

 The answer is (c) K

• K has largest atomic radii because atomic radii decreases from left to right along a period. 
• This is because of increase in nuclear charge which tends to pull the electron closer to the nucleus and reduces the size of the atom. 
• Hence K has the largest atomic radii.

(a) - (E)

(b) - (A)

(c) - (D)

(d) - (B)

(e) - (C)

The answer is (b) Na

Na and K belongs to the same group I and Magnesium and Calcium belongs to group II. Sodium has 1 electron in its valence shell which can be lost easily.

The pairs of elements would produce a covalent bond is-

C and D.

(a) B and C.

(b) A and C .

(a) show same atomic mass

• Ionization is always an endothermic process. It absorbs energy.
• Ionization energies always increase in the order, I.E₁ < I.E₂ < I.E₃.
• Ionization energy measurements are carried out with atoms in the gaseous state.

(i) ‘M’ and ‘N’ belong to the same period but group I and II respectively. N is smaller than M as the atomic size decreases on moving from left to right across the Periodic Table. 

(ii) M is more metallic than ‘N’ because metallic character decreases from left to right as tendency to lose electrons decreases due to decrease in atomic size. 

(iii) The valencies of M and N are 1 and 2 respectively, valency across the period first increases then decreases. 

(iv) MCl and NCl₂.

The answer is (d) (ii) and (iv)

Elements with same atomic number but different atomic masses are known as isotopes. Isotopes same chemical properties but differ in their physical properties.

Characteristics of a group: 

(a) Valence electrons → All elements show same valence electrons in a group. 

(b) Valency → Valency of all the elements remains the same in a group. 

(c) Atomic size → The atomic size goes on increasing down the group. 

(d) Metallic character → In case of metals the metallic character increases down the group. 

(e) Non-metallic character → In case of non-metals the non-metallic character decreases down the group.

The vertical column in the Periodic Table are called ‘groups’, the horizontal rows in the table are called periods.

In a period as we go from left to right: 

(a) Valence electrons → Goes on increasing 

1, 2, 3, 4, 5, 6, 7, 8. 

(b) Valency → Valency first increases and then decreases 1, 2, 3, 4, 3, 2, 1, 0. 

(c) Size of atom → Size of atom goes on decreasing 

(d) Metallic character → Decreases 

(e) Non-metallic character → Increases

All elements in the same column of the periodic table as boron have 3 valence electrons.

(a) Neon
(b) Magnesium
(c) Silicon
(d) Boron
(e) Carbon

All elements in fluorine group have valency 1.

All elements in Boron group have valency 3.

Answer :
(a) All the elements in the same column as boron have the same number of valence electrons (3). Hence, they all have valency equal to 3.
(b) All the elements in the same column as fluorine have the same number of valence electrons (7). Hence, they all have valency equal to 1.

The element fluorine is in group 17 o f the periodic table and has a valency of 1. So, all the elements in the same group of periodic table as fluorine will have a valency of 1.

Correct option is (d) S < P < O < N

Electromagnetic energy depends on two factors 

1. wavelength 

2. frequency.

The Quantum mechanical model of an atom was developed by Erwin Schrodinger.

Yes, sodium vapours produce yellow light in street lamps.

Correct option is  B) Sodium

Stationary states are also called energy levels.

The disturbance occurred in a medium is called wave.

Yes. The electrons present in atoms of elements absorb energy and move to excited states and they return to ground state with emission of energy in visible spectrum. So the colours observed during fire works are the emitted energy by various elements in different fire works.

Correct option is  A) red

Correct option is  B) red

The atomic spectrum of a hydrogen atom is a line spectrum.

Answer is : Green colour.

Correct option is  B) green

While heating the rod if the temperature is high enough, other colours will also be emitted, but due to higher intensity of one particular emitted colour (eg.: red), others cannot be observed.

Line spectrum is also known as discrete spectrum.

Helium (1s²)

1. When we heat an iron rod, some amount of heat energy that was absorbed by iron rod is emitted as light. 

2. First iron turns into red (lower energy corresponding to higher wavelength) and as the temperature rises it glows and turns into orange, yellow, blue or even white respectively (higher energy and lower wavelength). 

3. If we go on heating the rod, it turns into white light which includes all visible wavelengths. 

4. So we find some changes in colour while heating an iron rod.

Sodium vapour lamp emits light of the wavelengths 589.0 nm to 589.6 nm.

Planck’s equation is E = hv. 

E = Energy of the radiation 

h = Planck’s constant = 6.625 × 10^-34 J 

v = Frequency of radiation.

Configuration of oxygen is 1s² 2s²2p⁴ . The added electron is 4th in the 2p. The set of quantum numbers (2, 1, -1, -1/2)

Yes. It is a universal relationship and applies to all waves.

The value of Planck’s constant is 6.626 × 10^-34 Js.

An atom or molecule in an excited state can emit light to lower its energy in order to get stability.

The relation between frequency and velocity of light is c = vλ.

The electromagnetic wave has a speed of light, i.e. 3 × 10⁸ ms^-1

Yes. It is a universal relationship and applies to all waves.