Advertisements
Advertisements
प्रश्न
If an atom ‘A’ has atomic number 19 and mass number 39, state –
- Its electronic configuration.
- The number of valence electrons it possesses.
Advertisements
उत्तर
Atom ‘A’ has mass number A = 39 and atomic number Z = 19 = p
∴ A = Z + n
A = p + n
39 = 19 + n
n = 39 – 19 = 20
But e = p = 19
- A (K, L, M, N)
19 = 2, 8, 8, 1
There will be 2 electrons in K-shell or 1st shell
8 electrons in 2nd shell or L-shell
8 electrons in 3rd shell or M-shell
1 electron in 4th shell or nth-shell - The number of valence electrons i.e. in outer most shell = 1 electron.
APPEARS IN
संबंधित प्रश्न
FILL IN THE BLANK
Rutherford won the Nobel Prize in 1908 for his investigations in the field of ......................
WRITE SHORT ANSWER
Define the atomic mass number of an atom.
An element has an atomic number 12. How many electrons will be present in the K, L and M energy shells of its atom?
(a) What is meant by (i) atomic number, and (ii) mass number, of an element? Explain with the help of an example.
(b) What is the relation between the atomic number and mass number of an element?
(c) If an element M has mass number 24 and atomic number 12, how many neutrons does its atom contain?
The atom of an element X has 7 electrons in its M shell.
What is the atomic number of element X?
Sulphur has an atomic number 16 and a mass of 32.
State the number of protons and neutrons in the nucleus of sulphur. Give a simple diagram to show the arrangement of electrons in an atom of sulphur.
Match the atomic numbers 4,8,10,15 and 19 with the following:
Element with four shells
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]
Compare the charge and mass of protons and electrons.
Ca2+ has completely filled outer shell. Justify your answer.
