Atomic Structure and Radioactivity - SS1 Physics Past Questions and Answers - page 1
Which of the following is the correct definition of an atom?
A tiny particle that cannot be divided into smaller parts.
The smallest unit of matter that retains the properties of an element.
A combination of protons, neutrons, and electrons.
A subatomic particle with a positive charge.
What is the overall charge of an atom?
Positive
Negative
Neutral
Variable
Which subatomic particle has a positive charge?
Proton
Electron
Neutron
Nucleus
What is the approximate mass of an electron compared to a proton?
Equal to the mass of a proton
Twice the mass of a proton
Much smaller than the mass of a proton
Much larger than the mass of a proton
The atomic number of an element represents the number of:
Protons in the nucleus
Electrons in the nucleus
Neutrons in the nucleus
Electrons in the electron cloud
Which of the following subatomic particles is located outside the nucleus of an atom?
Proton
Electron
Neutron
Nucleus
The mass number of an atom is equal to the sum of:
Protons and electrons
Protons and neutrons
Electrons and neutrons
Protons, neutrons, and electrons
Describe the structure of an atom and the roles of its subatomic particles.
An atom consists of three main subatomic particles: protons, neutrons, and electrons. Protons have a positive charge and are located in the nucleus at the centre of the atom. Neutrons have no charge and also reside in the nucleus. Electrons have a negative charge and orbit around the nucleus in energy levels or electron shells. Protons and neutrons contribute to the mass of the atom, while electrons are much smaller and have negligible mass.
Explain the concept of atomic number and how it relates to the identity of an element.
The atomic number of an element represents the number of protons in the nucleus of an atom. It uniquely identifies an element because each element has a distinct number of protons. For example, hydrogen has an atomic number of 1, indicating it has one proton, while helium has an atomic number of 2, indicating it has two protons. The atomic number determines the element's position on the periodic table and its chemical properties.
Which subatomic particle has a positive charge?
Proton
Neutron
Electron
Nucleus