Atoms contain three different types of subatomic particles: protons, neutrons, and electrons.
Which one of these three particles has a negative electrical charge?
Which one of these three particles has a relative mass of 1 and no electrical charge?
Use words from the box below to complete the sentences. Each word may be used once, more than once, or not at all.
| electrons | elements | molecules | neutrons | protons |
|---|
(i) Atoms are neutral because they contain equal numbers of ____________ and ____________.
(ii) Isotopes are atoms of the same element with the same number of ____________ but different numbers of ____________ in the nucleus.
An atom of potassium can be represented by the symbol 1939K^{39}_{19}\text{K}1939K.
Use numbers to complete these statements about this atom:
(i) The atomic number of this atom is ____________.
(ii) The mass number of this atom is ____________.
(iii) The electronic configuration of this atom is ____________.
