Which of the following atoms and ions are isoelectronic,i.e.,have the same number of electrons as the neon atom?

An atom has a mass number of $25$ and contains $13$ neutrons in its nucleus. What is the charge of its ion if it forms a stable octet?

In the neutral state,the element $M$ consists of the isotopes $_{14}M^{28}$,$_{14}M^{29}$,and $_{14}M^{30}$ in the ratio $60 : 30 : 20$ respectively. Correct statements about $M$ in the natural state include that:

How many neutrons are present in the nucleus of $_{88}Ra^{226}$?

Assertion : Atoms are not electrically neutral.
Reason : Number of protons and electrons are different.

Find the number of neutrons,electrons,and protons in the following species:
$(i)$ $_{15}^{31}P$
$(ii)$ $_{11}^{23}Na^{+}$
$(iii)$ $_{16}^{32}S^{2-}$
$(iv)$ $_{101}^{235}X$
$(v)$ $_{20}^{40}Ca^{2+}$
$(vi)$ $_9^{19}F^{-}$