Question

A tripositive ion has protons whose mass is equal to 23881 times that of an electron. Identify the element.

• A. Aluminium
• B. Silicon
• C. Magnesium
• D. Boron

Answer 1

The correct option is A Aluminium

Let the number of protons be $p$ and electrons be $e$

then, in the given tripositive ion, $e=p-3$

given $m_p=23881\times$ mass of electron

Mass of electrons $m_e=9.1\times {10}^{-31}kg$

Mass of protons in the atom $m_p$=mass of one proton $\times$ p

$m_p=1.67\times {10}^{-27}\times pkg$

Also, $1.67\times {10}^{-27}\times p=23881\times 9.1\times {10}^{-31}$

$p=13$ and $e=13-3=10$

thus the atom is Aluminium as ${}_{13}A{l}^{+3}$

option A is correct