1(b) An electron is much heavier than a proton.

1(c) The nucleus of an atom is positively charged.

2(a). What is (a)?

2(b). What is (b)?

2(c). What is (c)?

2(d). What is (d)?

2(e). What is (e)?

3(a). A particular atom of an element has an atomic number of 18 and a mass number of 40. How many protons and neutrons does it have respectively?

3(b). A particular atom of an element has an atomic number of 18 and a mass number of 40. How many electrons does it have?