Atoms, elements and compounds - Atomic structure and the Periodic Table (3)
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1.
Define the term proton number or atomic number. Explain its significance in identifying an element.
The proton number, also known as the atomic number, is defined as the number of protons present in the nucleus of an atom. It is a fundamental characteristic of an element.
Significance: The proton number uniquely identifies an element. All atoms of a particular element, regardless of their mass or isotopic variations, have the same number of protons. Therefore, the atomic number defines the element. For example, all atoms with 6 protons are carbon atoms.
2.
Explain, in terms of the number of protons, how isotopes of an element differ, yet still represent the same element.
Isotopes are atoms of the same element, meaning they have the same number of protons (and therefore the same atomic number). However, isotopes differ in the number of neutrons in their nucleus.
Because isotopes have the same number of protons, they are defined as the same element. The difference in the number of neutrons leads to variations in their mass number. For example, Carbon-12 (12C) and Carbon-14 (14C) are isotopes of carbon; both have 6 protons, but 12C has 6 neutrons and 14C has 8 neutrons.
3.
The atomic number of an element is defined as the number of ________ in the nucleus. What is the relative charge and relative mass of these particles?
| Particle |
| Relative Charge | Relative Mass |
Proton:
- Relative Charge: +1
- Relative Mass: 1
Neutron:
- Relative Charge: 0
- Relative Mass: 1
Electron:
- Relative Charge: -1
- Relative Mass: 0