Chemistry
The nucleus of element with 2 electrons in 'K' shell & 1 electron in 'M' shell.
- is 3919X
- has 12 neutrons
- has 19 protons
- has equal no. protons & neutrons
Answer
has 12 neutrons
Reason — The electronic configuration is 2, 8, 1
The element has 11 electrons. Hence, the atomic number (Z) = 11.
Sodium has atomic number (Z) 11.
Mass number of sodium (A) is 23.
Number of neutrons = Mass number (A) - Atomic number (Z)
= 23 - 11
= 12
So, the element has 12 neutrons.
Related Questions
Differentiate between the terms —
Duplet and octet rule.
Explain the octet rule for formation of —
(a) Sodium chloride from a sodium atom and a chlorine atom.
(b) Nitrogen molecule from two nitrogen atoms.
Which of the following is correct in an element AZY.
- Number of neutrons = Z-A
- Number of protons = A
- Z = sum of protons & electrons
- A = sum of neutrons & electrons
Assertion: Elements 11H, 21H, 31H have different number of neutrons.
Reason: Isotopes have the same atomic number.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true and R is not the correct explanation of A.
- A is true and R is false.
- A is false and R is true.