The Fundamental Unit Of Life

Question

The mass number of an element is 18. It contains 9 electrons. What is the no. of protons, neutrons? What is the atomic no. of the element

Solution

The mass number of the atom is given by the formula,
mass number = Total number of protons + Total number of neutrons.

(i) Number of protons = no. of electrons = 9

(ii) Number of neutrons = mass no. - no. of protons = 18 - 9 = 9

∴
(iii) Atomic number = no. of protons = 9.

The atomic number of electron is 9. Element is Fluorine.

Some More Questions From The Fundamental Unit of Life Chapter

Na⁺ has completely filled K and L-shells. Explain.

If Z = 3, what would be the valency of the element? Also, name the element.

Composition of the nuclei of two atomic species X and Y are given as under

X Y
Protons = 6 6
Neutrons= 6 6

Give the mass numbers of X and Y. What is the relation between the two species?

For the following statements, write T for True and F for False.

(a) J.J. Thomson proposed that the nucleus of an atom contains only nucleons.

(b) A neutron is formed by an electron and a proton combining together. Therefore, it is neutral.

(c) The mass of an electron is about 1/2000 times that of proton.

(d) An isotope of iodine is used for making tincture iodine, which is used as a medicine.

Rutherford’s α-particle scattering experiment was responsible for the discovery of

Isotope of an element has

Number of valence electrons in Cl^- ion are

Which one of the following is a correct ? Electronic configuration of sodium

(a) 2, 8,2 (b) 8, 2, 1 (c) 2, 1, 8 (d) 2, 8, 1.

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

-

1

0

-

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The Fundamental Unit Of Life

The mass number of an element is 18. It contains 9 electrons. What is the no. of protons, neutrons? What is the atomic no. of the element

Some More Questions From The Fundamental Unit of Life Chapter

Na⁺ has completely filled K and L-shells. Explain.

If Z = 3, what would be the valency of the element? Also, name the element.

Composition of the nuclei of two atomic species X and Y are given as under

X Y
Protons = 6 6
Neutrons= 6 6

Give the mass numbers of X and Y. What is the relation between the two species?

Rutherford’s α-particle scattering experiment was responsible for the discovery of

Isotope of an element has

Number of valence electrons in Cl^- ion are

Which one of the following is a correct ? Electronic configuration of sodium

(a) 2, 8,2 (b) 8, 2, 1 (c) 2, 1, 8 (d) 2, 8, 1.

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

-

1

0

-

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

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Loaction

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	-	1	0	-

For Daily Free Study Material Join wiredfaculty

The Fundamental Unit Of Life

The mass number of an element is 18. It contains 9 electrons. What is the no. of protons, neutrons? What is the atomic no. of the element

Some More Questions From The Fundamental Unit of Life Chapter

Na+ has completely filled K and L-shells. Explain.

If Z = 3, what would be the valency of the element? Also, name the element.

Composition of the nuclei of two atomic species X and Y are given as under X Y Protons = 6 6 Neutrons= 6 6Give the mass numbers of X and Y. What is the relation between the two species?

Rutherford’s α-particle scattering experiment was responsible for the discovery of

Isotope of an element has

Number of valence electrons in Cl- ion are

Which one of the following is a correct ? Electronic configuration of sodium (a) 2, 8,2 (b) 8, 2, 1 (c) 2, 1, 8 (d) 2, 8, 1.

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 - 1 0 -

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

Na⁺ has completely filled K and L-shells. Explain.

Composition of the nuclei of two atomic species X and Y are given as under

X Y
Protons = 6 6
Neutrons= 6 6

Give the mass numbers of X and Y. What is the relation between the two species?

Number of valence electrons in Cl^- ion are

Which one of the following is a correct ? Electronic configuration of sodium

(a) 2, 8,2 (b) 8, 2, 1 (c) 2, 1, 8 (d) 2, 8, 1.

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

-

1

0

-