The number of neutrons in the element 4 Be 9 is :

Question

The number of neutrons in the element 4 Be 9 is : (A) 3 (B) 5 (C) 7 (D) 9

Tardigrade Admin · Accepted Answer

We know that Atomic number = number of protons = number of electrons Mass number = number of proton + number of neutrons ∴ number of neutrons = mass number - atomic number =9-4=5

Q. The number of neutrons in the element $_{4} B e^{9}$ is :

3

5

7

9

We know that Atomic number = number of protons = number of electrons Mass number = number of proton $+$ number of neutrons
$∴$ number of neutrons = mass number $-$ atomic number
$= 9 - 4 = 5$

Q. The number of neutrons in the element 4​Be9 is :

3

5

7

9

We know that Atomic number = number of protons = number of electrons Mass number = number of proton + number of neutrons ∴ number of neutrons = mass number − atomic number =9−4=5

Q. The number of neutrons in the element $_{4} B e^{9}$ is :

We know that Atomic number = number of protons = number of electrons Mass number = number of proton $+$ number of neutrons
$∴$ number of neutrons = mass number $-$ atomic number
$= 9 - 4 = 5$