no
End use, fit and how much money you have
.223 Calibre although .223 Will fit on a 5.65 mm, a 5.65 mm Will not fit in a .223 calibre chamber.
No. If it does not have 5.56 on the barrel then use .223 ammo.
Magazine, not clip. Also, yes, it appears that the R-15 can take STANAG magazines (which are the magazines that the AR-15 rifle takes).
The second electron shell can hold a maximum of 8 electrons.
Made in Bayonne, France, those are called bayonets.
No
No, it does not.
No they won't fit. If you force it, it will ruin the rifle.
The question is vague, as shell can mean valence shell or inner shells that can also fit atoms via 'sharing' for transition metals, however, the number of atoms that can fit would determine on the number of electrons and vacant spots available for sharing on the outermost electronic shell. (Assume the question in mind is for covalent bonding; does not apply to ionic bonding.)
NO I is like a snail a shell but no bones. they wouldn't be compact enough to fit in the shell
Two electrons can fit in the first shell