Questions in atomic-structure

Select	Question
	Which of the following oxides of nitrogen is isoelectronic with $C{O_2}$
	The ratio between the neutrons in $C$ and $Si$ with respect to atomic masses $12$ and $28$ is
	The atomic number of an element is always equal to
	Which of the following is isoelectronic with carbon atom
	$C{O_2}$ is isostructural with
	The hydride ions $({H^ - })$ are isoelectronic with
	The number of electrons in the nucleus of ${C^{12}}$ is
	An element has electronic configuration $2$,$8$,$18$,$1$. If its atomic weight is $63$,then how many neutrons will be present in its nucleus
	The nucleus of the element $_{21}{E^{45}}$ contains
	Neutrons are found in atoms of all elements except in