R15 revision

What does an atom contain?

• A positively charged nucleus with orbiting negatively charged electrons

• A nucleus containing only protons and neutrons

• The same mass for protons and neutrons but different for electrons

• No overall electrical charge

Answer explanation

An atom contains a positively charged nucleus with orbiting negatively charged electrons.

What is found in the nucleus of an atom?

• Electrons and protons

• Protons and neutrons

• Neutrons and electrons

• Protons only

Answer explanation

The nucleus of an atom contains protons and neutrons, not electrons. Electrons are found outside the nucleus in electron shells.

What are the relative masses and charges of protons, neutrons, and electrons?

• Protons and neutrons have the same mass of 1 amu and electrons have a negligible mass

• Protons have a positive (+1), neutrons are neutral (0), and electrons have a negative (-1) charge

• Protons, neutrons, and electrons all have the same mass

• Protons and electrons are positive, neutrons are negative

Answer explanation

Protons have a positive (+1), neutrons are neutral (0), and electrons have a negative (-1) charge

What characterises atoms that have no overall electrical charge?

• They have an equal number of protons and electrons

• They contain only neutrons

• They have more protons than electrons

• They have more electrons than protons

Answer explanation

Atoms with no overall electrical charge have an equal number of protons and electrons.

What do the terms atomic number, mass number, and isotope refer to?

• Differences in the number of protons, neutrons, and electrons in an atom

• Differences in atomic mass and isotopes based on neutron count

• Descriptions of atomic structure including protons, neutrons, and isotopic variations

• Only the variations in electron configurations

Answer explanation

Descriptions of atomic structure including protons, neutrons, and isotopic variations

How are the numbers of protons, neutrons, and electrons in an atom related to its atomic number and mass number?

• The atomic number equals the number of protons, and the mass number equals the sum of protons and neutrons

• The atomic number equals the number of electrons, and the mass number equals the sum of electrons and neutrons

• The atomic number equals the number of neutrons, and the mass number equals the sum of protons and electrons

• None of the above

Answer explanation

The atomic number equals the number of protons, and the mass number equals the sum of protons and neutrons

How is the relative atomic mass of elements with more than one isotope calculated?

• By averaging the masses of the isotopes based on their abundance

• By adding the masses of the isotopes

• By multiplying the atomic number by the number of isotopes

• By using only the heaviest isotope

Answer explanation

By averaging the masses of the isotopes based on their abundance

How are elements arranged in the modern Periodic Table?

• By increasing atomic number and similar chemical properties in groups

• By decreasing atomic mass

• By alphabetical order of element names

• Randomly based on the discovery date of elements

Answer explanation

By increasing atomic number and similar chemical properties in groups

Explain how the electronic structure of any element is related to its position in the Periodic Table.

• The electronic structure determines the element's group and period.

• The electronic structure is unrelated to the element's position.

• The electronic structure only determines the element's color.

• The electronic structure is determined by the element's atomic mass.

Answer explanation

The electronic structure determines the element's group and period.

Which of the following statements best describes the similarities and trends in physical and chemical properties of elements in the same group, as illustrated by Group 1 and Group 7?

• Elements in the same group show similar chemical properties but different physical properties.

• Elements in the same group show similar physical properties but different chemical properties.

• Elements in the same group show both similar physical and chemical properties.

• There are no clear trends or similarities in properties of elements within the same group.

Answer explanation

Elements in the same group show similar chemical properties but different physical properties.