Excellent! $$\text{No. of protons}$$ $$\, = \text{Atomic Number} = 12$$
$$\text{No. of protons}$$ $$+ \, \text{No. of neutrons}$$ $$=\text{Mass Number} = 26$$. Thus, $$\text{Number of neutrons} = 26 - 12 = 14$$
Consider these two atoms: $$^1_1 X$$ and $$^2_1 Y$$. Will their chemical properties be similar?