Advertisements
Advertisements
प्रश्न
Which of the following are isoelectronic species i.e., those having the same number of electrons?
Na+, K+, Mg2+, Ca2+, S2–, Ar
Advertisements
उत्तर
Isoelectronic species have the same number of electrons.
Number of electrons in sodium (Na) = 11
Number of electrons in (Na+) = 10
A positive charge denotes the loss of an electron.
Similarly,
Number of electrons in K+ = 18
Number of electrons in Mg2+ = 10
Number of electrons in Ca2+ = 18
A negative charge denotes the gain of an electron by a species.
Number of electrons in sulphur (S) = 16
∴ Number of electrons in S2- = 18
Number of electrons in argon (Ar) = 18
Hence, the following are isoelectronic species:
1) Na+ and Mg2+ (10 electrons each)
2) K+, Ca2+, S2– and Ar (18 electrons each)
APPEARS IN
संबंधित प्रश्न
The composition of the nuclei of two atomic species X and Y are given as under
| X | Y | |
| Protons | 6 | 6 |
| Neutrons | 6 | 8 |
Give the mass numbers of X and Y. What is the relation between the two species?
Complete the following table.
| Atomic number | Mass number | Number of Neutrons | Number of protons | Number of electrons | Name of the Atomic species |
| 9 | - | 10 | - | - | - |
| 16 | 32 | - | - | - | Sulphur |
| - | 24 | - | 12 | - | - |
| - | 2 | - | 1 | - | - |
| - | 1 | 0 | 1 | 0 | - |
Fill in the blank
An ion which has a positive charge is called a ..................
Multiple Choice Questions
The sub atomic particle with negative charge is
The atom of an element is made up of 4 protons, 5 neutrons and 4 electrons. What is its atomic number and mass number?
FILL IN THE BLANK
Rutherford won the Nobel Prize in 1908 for his investigations in the field of ......................
TRUE \ FALSE
After the emission of a beta-particle, the atomic number of the atom increases by one.
ÅIn group I of the periodic table, three elements X, Y, and Z have ionic radii 1.33 Å, 0.95 Å and 0.60 Å respectively. Giving a reason, arrange them in the order of increasing atomic number in the group.
An element has an atomic number 12. How many electrons will be present in the K, L and M energy shells of its atom?
Fill in the following blanks :
| Atomic Number | Mass Number | Protons | Neutrons | Electrons | Symbol |
| 10 | 22 | _________ | _________ | _________ | _________ |
The number of electrons in the atom of an element X is 15 and the number of neutrons is 16. Which of the following is the correct representation of an atom of this element ?
The atom of an element is made up of 4 protons, 5 neutrons and 4 electrons. What are its atomic number and mass number?
An element A atomic number 7 mass numbers 14
B electronic configuration 2,8,8
C electrons 13, neutrons 14
D Protons 18 neutrons 22
E Electronic configuration 2,8,8,1
State Valency of each element
An element A atomic number 7 mass numbers 14
B electronic configuration 2,8,8
C electrons 13, neutrons 14
D Protons 18 neutrons 22
E Electronic configuration 2,8,8,1
State (i) Valency of each element (ii) which one is a metal (iii) which is non-metal (iv) which is an inert gas
What is meant by the 'atomic number of an element'?
If an atom ‘A’ has mass number 35 and atomic number 17, state the number of protons, electrons and neutrons it contains.
Draw the atomic diagram of the following element showing the distribution of – protons, neutrons and the electrons in the various shell of the atom.
Phosphorus – \[\ce{^31_15P}\]
[The upper number represent the – mass number and the lower number represent the – atomic number e.g. calcium – mass number = 40, atomic number = 20]
Draw the atomic diagram of the following element showing the distribution of – protons, neutrons and the electrons in the various shell of the atom.
Calcium – \[\ce{^40_20Ca}\]
[The upper number represent the – mass number and the lower number represent the – atomic number e.g. calcium – mass number = 40, atomic number = 20]
From the symbol \[\ce{^4_2He}\] for the element helium, write down the mass number and the atomic number of the element.
Elements X, Y, Z have atomic numbers 6, 9 and 12 respectively. Which one:
- forms anion – negative ion;
- forms cation – positive ion;
- has 4 electrons in the outermost orbit. [Y, Z, X]
