Advertisements
Advertisements
Question
Draw the structure of the following atoms showing the nucleus containing – protons, neutrons and the orbits with the respective electron:
Lithium [At. no. = 3, Mass no. = 7]
Advertisements
Solution
Structure of atoms:
Z is Atomic Number A is the mass number
Lithium \[\ce{^7_3Li}\]
Z = 3 = p = e
K L
e = 3 = 2, 1
A = p + n
7 = 3 + 3
∴ n = 7 − 3 = 4
APPEARS IN
RELATED QUESTIONS
Explain the Mass number with example.
Write true or false for the following statement
An atom on the whole has a positive charge.
Multiple Choice Questions
The sum of number of protons and number of neutrons present in the nucleus of an atom is called its
TRUE \ FALSE
After the emission of a beta-particle, the atomic number of the atom increases by one.
The atomic number of four elements A, B, C and D are 12, 13, 15 and 3 respectively. The element which cannot form a cation is :
An atom of an element has two electrons in the M shell.
What is the (a) atomic number (b) number of protons in this 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 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
If an atom ‘A’ has atomic number 19 and mass number 39, state –
- Its electronic configuration.
- The number of valence electrons it possesses.
What is common salt? Name the elements present in it. Write the formula of common salt. What are the atomic number and the mass number of the elements? Write the ions in the compound.
Match the following:
| Column A | Column B | ||
| 1. | K shell | a. | 8 |
| 2. | L shell | b. | 32 |
| 3. | M shell | c. | 2 |
| 4. | N shell | d. | 18 |
