Classification of Elements and Periodicity in Properties Test - 12

Because CS is Greater size than Lithium and Iodine has greater size than fluorine.

\(\mathrm{O^{2-}, S^{2-}}\) both has less affinity less than 0

Electronegativity is the property of a bonded atom. The relative tendency on an atom to attract the shared pair of electron toward itself is called electronegativity.

Amongst B, C, N, and O, N has the highest first ionization energy, because of its half-filled 2p orbital which is more stable.

After fluorine, the most electronegativity element is oxygen as per Pauling's scale of electronegativity.

\(_XF = 4.0, _XCl = 3.0, _XO = 3.5, _XS = 2.5\)

The element with the lowest ionization energy is cesium (Cs). Cesium has atomic number 55 and is in the fifth row of the periodic table.

Each period consists of a series of elements whose atom have the same principal quantum no. (n) of the outer most shell i.e. In second period n = 2, this shell has four orbitals (one 2s and three 2p) which can have eight electrons, hence second period contains 8 elements from atomic no. 3 to 10.

The energy required to remove an electron from outermost orbit of an isolated gaseous atom is called I.E. Now carbon has \(4e^-\) in outermost shell(Shell structure is 2.4). Thus it has 6 ionization energies.

The electron affinities of some of the elements of second period (i.e., N, O, F etc.) are, however, lower than the corresponding elements (i.e., P, S, Cl, etc.) of the third period. This is due to the reason that the elements of second period have the smallest atomic size amongst the elements in their respective groups.

 As a result, there is considerable electron-electron repulsion within the atom itself and hence the additional electron is not accepted with the same ease as is the case with the remaining elements in the same group.

In \(BeCl_2\) has the highest melting point due to ionic bond.

Calcium has the greater tendency to form metal oxide. K and Na react violently with cold water whereas Ca readily reacts with cold water.

When we move from left to right in the Periodic Table, atomic radius decreases.

While in a group atomic radius, it increases from up to down. Moreover, the radius of alkali metals is metallic radius and that of halogens is covalent radius and metallic radius > covalent radius. 

Thus, Br has the smallest atomic radius.

As Flourine has most electronegative character, it was expected to have highest electron affinity.

However, Flourine has less electron affinity due to more electrostatic repulsive forces in small 2P orbitals. So chlorine has most electron affinity.

(i) In nitrogen p - sub shell is half-filled. According to Hund, half-filled & full-filled orbitals are more stable.

(ii) Hence it is difficult to remove an electron from 2p, so more amount of energy is required to remove an electron. Therefore IE of nitrogen is higher than oxygen.

Molybdenum is a chemical element with the symbol Mo and atomic number 42. Molybdenum does not occur naturally as a free metal on Earth; it is found only in various oxidation states in minerals.

32 elements are the in 5th period.

(i) Dubnium is a synthetic chemical element with the symbol Db and atomic number 105.

(ii) Dubnium is highly radioactive: the most stable known isotope, dubnium-268, has a half-life of about 28 hours.

(iii) This greatly limits the extent of research on dubnium.

Rare earth metals and alloys that contain them are used in many devices that people use every day such as computer memory, DVDs, rechargeable batteries, cell phones, catalytic converters, magnets, fluorescent lighting.

The number of naturally occurring p-block elements that are diamagnetic is five.