English Medium Class 9 - CBSE Question Bank Solutions

Name the particles which actually determine the mass of an atom.

Fill in the blanks- The number of protons in the nucleus of an atom is called its ....................

Fill in the blank of the following statement : 

The total number of protons and neutrons in the nucleus of an atom is called its _________.

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 ___________.

(a) Which of the nuclear particles is present in the same fixed number in the atoms of any particular element?

(b) What do we call this number which is characteristic of a particular element?

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 :

Fill in the following blanks in respect of an atom of an element 

 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?

The mass number of an element is 23 and it contains 11 electrons. What is the number of protons and neutrons in it? What is the atomic number of the element?

(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 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 ?

From the symbol `""_15^31"P"`, state :
(i) mass number of phosphorus,
(ii) atomic number of phosphorus, and
(iii) electron configuration of phosphorus.

From the symbol `""_15^31"P"`, state :  atomic number of phosphorus

The atom of an element X has 7 electrons in its M shell.
What is the atomic number of element X?

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 :

Find the ratio by mass of the combining elements in the following compounds. (You may use Appendix-III)

CaCO₃

Find the ratio by mass of the combining elements in the following compounds. (You may use Appendix-III)

MgCl₂

Find the ratio by mass of the combining elements in the following compounds. (You may use Appendix-III)

H₂SO₄