Answer is: formula of the complex is [Cr(NH₃)₂(SCN)₄<span>]</span>⁻<span>.
This complex has negative charge (-1) because chromium (central atom or metal) has oxidation number +3, first ligand ammonia has neutral charge and second ligand thiocyanate has negative oxidation number -1:
+3 + 2</span>·0 + 4·(-1) = -1.
The answer is A. same atomic number; different number of protons
Hello!
CH3(CH2)4CCH
or <span> C7H12
</span>

<span>hydrocarbon: </span>
1-heptyne