I did bad in my Chemistry Unit TestWatch
.Also, I got 11/40 and I did so bad :C
Secondly, chemical properties are not due to the number of electrons, but the element itself. Eg A Magnesium +1 ion reacts differently to sodium, but they have the same number of electrons. (1s2,2s2,2p6,3s1) Electrons I suppose consitutute reactive properties, like what charge of ion it forms, the energy required to break the ionic bond, etc.
Isotopes have similar chemical properties, (boiling/ melting point, flammability etc) as they have the same number of protons and electrons. Remember in an isotope only the number of neutrons are different, and the protons and electrons define an element. Physical properties may be different, eg some isotopes are unstable, they boil at different temperatures, odd numbers of neutrons create a "spin" effect.
I'm not an expert chemist, but I assume you should have written that the number of protos and electrons are the same, not just electrons.
Also you could always ask your chem teacher to go through the test with you one lunch or something, im sure they would be fine doing that.