Advertisements
Advertisements
प्रश्न
Taking into consideration the period of the elements given below, answer the following questions:
| Elements | Atomic Radius (pm) |
| O | 66 |
| B | 88 |
| C | 77 |
| N | 74 |
| Be | 111 |
| Li | 152 |
- Arrange the above elements in decreasing order of their atomic radii.
- State the period to which the above elements belong.
- Why this arrangement of elements is similar to the above period of modern periodic table?
- Which of the above elements have the biggest and the smallest atom?
- What is the periodic trend observed in the variation of atomic radius while going from left to right within a period?
Advertisements
उत्तर
- Li > Be > B > C > N > O
- 2nd period
- Yes, this elemental arrangement resembles the era of the contemporary periodic table mentioned above. The positive charge on the nucleus grows one unit at a time as we move from left to right over a period of time, but when electrons are added to the same orbit, the pull away from the nucleus increases, reducing the size of the atom.
- Li is the biggest atom oxygen is the smallest atom
- While going from left to right within a period atomic radius decreases due to an increase in effective nuclear charge.
APPEARS IN
संबंधित प्रश्न
How do the atomic size and metallic character of elements vary as we move :-
(a) down a group and
(b) from left to right in a period
Define the term : Atomic size
Write any one difference in the electronic configurations of group-1 and group-2 elements ?
Match the atomic number 2, 4, 8, 15 and 19 with each of the following
1) A solid non metal belonging to the third period.
2) A metal of valency 1.
3) A gaseous element with valency 2.
4) An element belonging to Group 2
5) A rare gas.
Differentiate between Normal elements and Transition elements.
What happens to the metallic character of the elements as we go down in a group of the periodic table?
Rewrite the following statement after correction, if necessary:
The metallic character of elements in a period increases gradually on moving from left to right.
How does the electropositive character of elements change on going down in a group of the periodic table?
For each of the following triads, name the element with the characteristics specified below:
| Elements | Least atomic radius | Chemically least reactive |
| (i) F, Cl, Br (ii) Li, Na, K |
.................... .................... |
.................... .................... |
State one reason for keeping fluorine and chlorine in the same of the periodic table.
Name two properties of elements whose magnitudes change when going from top to bottom in a group of the periodic table. In what manner do they change?
The element which has the maximum number of valence electrons is:
(a) Na
(b) P
(c) Si
(d) A
In each of the following pair, choose the atom having the bigger size:
Na (At. No. 11) or K (At. No. 19)
An element has 2 electrons in its N shell.
State the name assigned to this group.
Name the non-metals present in period 2 and metals in period 3.
Name the element of lower nuclear charge out of Be and Mg.
name the elements in period 1.
An element 'X' (Atomic number – 20) burns in the presence of oxygen to form a basic oxide.
(a) Identify the element and write its electronic configuration.
(b) State its group number and period number in the Modern Periodic Table.
(c) Write a balanced chemical equation for the reaction when this oxide is dissolved in water.
On the basis of electronic configuration, how will you identify the first and the last element of a period?
What is modern periodic law?
How many groups and periods are there in the modern periodic table?
What is meant by periodicity of elements?
Fill in the blank
There are ______ groups and ______ periods in the modern form of periodic table.
Atomic number of an element is 16. State
- the period to which it belongs
- the number of valence electrons
- whether it is a metal or non-metal
Choose the most appropriate answer from the following list of oxides which fit the description.
A basic oxide.
Arrange the following as per instruction given in the bracket.
Mg, Cl, Na, S, Si (decreasing order of atomic size)
Arrange the following as per instruction given in the bracket.
Cs, Na, Li, K, Rb (increasing metallic character)
Arrange the following as per instruction given in the bracket.
K, Pb, Ca, Zn (increasing reactivity)
The elements of one short period of the periodic table are given below in order from left to right:
| Li | Be | B | C | O | F | Ne |
Which one of the above elements belongs to the halogen series?
An element belongs to the third period and Group IIIA (13) of the periodic table. State: the number of valence electrons,
An element A has 2 electrons in its fourth shell. State:
its valency
Based on the group valency of element write the molecular formula of the following compound giving justification:
Halide of the elements of group thirteen
Name or state following with reference to the elements of the first three periods of the periodic table.
The number of electron shells in elements of period 1, period 2, and period 3.
Select the correct answer from the options given below.
It is a period having elements from atomic no. 11 to 18.
State the following:
The group which contains highly electropositive metals including sodium.
Complete the table pertaining to the following elements given in Column I.
| Column I Elements | Atomic Number | Electronic Configuration | Underline the element present in that group |
| 1. Hydrogen | 1 | ______ | Be/Na/Ca |
| 2. Carbon | 6 | ______, ______ | N/P/Si |
| 3. Nitrogen | 7 | _______, ______ | C/P/S |
| 4. Oxygen | 8 | _______, ______ | N/S/Cl |
| 5. Sulphur | 16 | _____, ______, _______ | O/N/F |
| 6. Chlorine | 17 | _____, ______, ______ | I/O/S |
Which of the following would weigh the least?
(Atomic masses C = 12, 0 = 16, Na = 23)
