Cracking the SAT Chemistry Subject Test

Remember    the following:

Neutrons:       •   along   with    protons,    make    up  the nucleus of  an  atom

        •   electrical  neutrality

        •   isotopes—two    atoms   of  the same    element are isotopes    if  they

differ  in  their   number  of  neutrons

Mass

number:

        •   number  of  protons plus    number  of  neutrons;

        •   isotopes—two    isotopes    of  an  element have    different   mass

numbers because they    differ  in  the number  of  neutrons

Atomic

weight:

        •   average of  mass    numbers for all isotopes    of  an  element as  they

occur   on  Earth

Now try the following questions. The answers can be found in Part III.