Advertisements
Advertisements
Question
Which of the following are isoelectronic species i.e., those having the same number of electrons?
Na+, K+, Mg2+, Ca2+, S2–, Ar
Advertisements
Solution
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)
RELATED QUESTIONS
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 | - |
What are the atomic numbers of elements whose outermost electrons is represented by 3p5?
The atomic number and the mass number of sodium are 11 and 23 respectively. What information is conveyed by this statement.
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 of the Following Statement :
An atom has atomic mass number 23 and atomic number 11. The atom has .................... electrons.
Fill in the blank of the following statement :
All the mass of an atom is concentrated in a small region of space called the ___________.
The mass number of an element is 18. It contains 7 electrons. What is the number of protons and neutrons in it? What is the atomic number of the element?
Define the following form:
Atomic number
The properties of the elements are a periodic function of their __________.
Match the atomic numbers 4,8,10,15 and 19 with each of the following:
An element which does not form ion
If an atom ‘A’ has atomic number 19 and mass number 39, state –
- Its electronic configuration.
- The number of valence electrons it possesses.
The atomic number and the mass number of an element is 26 and 56 respectively. Calculate the number of electrons, protons and neutrons in its atom. Draw the structure.
Every atom has an equal number of protons and electrons. The nature of the atom is ______.
The elementary particles such as protons and neutrons are collectively called ______.
‘Z’ is denoted by ______.
Mass No. 27 is for the element ______.
If an atom has 6 electrons in its outermost shell, it is inert.
An element has 2 electrons in its N shell.
What is its atomic number?
A group of elements in the periodic table is given below (Boron is the first member of the group and Thallium is the last).
Boron, Aluminium, Gallium, Indium, Thallium
Answer the following question in relation to the above group of elements:
The atomic number of boron is 5. Write the chemical formula of the compound formed when boron reacts with chlorine.
