Question

What are ‘periods’. State the correlation of a period number with the elements of that period.

July 25, 2024

Answer

Periods are the seven horizontal rows in the modern periodic table.

The number of shells in an atom determines it’s period. Hence, all the elements of a particular period have same number of shells as its period number.

💡 Some Related Questions

Arrange the following elements as per the guidelines in brackets.
(a) Na, Cl, Mg, P [in decreasing order of atomic size]
(b) C, Li, F, N [in increasing order of electronegativity]
(c) Cl, Al, Na, S [in increasing order of ionization potential]
(d) Li, F, C, O [in increasing order of electron affinity]
(e) Ar, He, Ne [in increasing order of number of electron shells]

Give reasons for the following:
If combining atoms have nearly similar electronegativities the bond between them is covalent.

Give reasons for the following:
Down a group electronegativity should increase with increase in nuclear charge but it is seen that the electronegativity decreases.

Give reasons for the following:
Atomic size of an element depends on the nuclear charge of that element.

Give reasons for the following:
Properties of elements are periodic functions of their atomic numbers and not atomic weights.

Give reasons for the following:
Occurrence of characteristic properties of elements takes place at definite intervals in the modern periodic table.

Match the elements in column ‘X’ with the correct group they belong from column ‘Y’
X Y
1: Element with atomic number 19 A: Group 18 [0 group]
2: Element with electronic configuration 2 B: Group 16 [VI A]
3: Element with a valency of -2 C: Group 1 [IA]
4: Element ‘P’ which loses 3 electrons to form a cation D: Group 17 [VII A]
5: Element ‘Q’ in period-3 which has the highest electron affinity E: Group 13 [III A]

With reference to group 1 [IA] of the periodic table – fill in the blanks with the correct word:
The elements are …………… [light/heavy] …………… [metals/non metals] since their atomic size is …………… [large/small]. The energy binding the atoms is …………… [high/low] and hence the elements have …………… [high/low] melting points. The melting points of the elements …………… [increases/decreases] down the subgroup. The electropositive character …………… [increases/decreases] down the subgroup and the elements are strong …………… [reducing/oxidizing] agents. The element with electronic configuration 2, 8, 1 will have …………… [higher/lower] electron affinity and …………… [smaller/larger] atomic size than the element with electronic configuration 2, 1.

With reference to period 3 of the periodic table — State :
(a) The type of bonding of the element with electronic configuration 2, 8, 7.
(b) The formula of the chloride of the element with electronic configuration 2, 8, 4.
(c) The nature of the oxide of the alkaline earth metal in the period.
(d) The number of electrons in the penultimate shell of the element with valency -1.
(e) The electronic configuration of the element whose hydroxide is a weak base.

In period 2, element ‘A’ is to the right of element ‘B’
(a) The element ‘A’ would probably have a …………… [smaller/larger] atomic size than ‘B’.
(b) The element ‘B’ would probably have …………… [lower/higher] ionization potential than ‘A’.
(c) The element ‘A’ would have …………… [lesser/higher] electron affinity than ‘B’.
(d) Nuclear charge of element ‘B’ would be …………… [less/more] than element ‘A’.
(e) If an element ‘C’ had a low electronegativity and ionization potential it would have more tendency to …………… [gain/lose] electrons.