原子結構與元素週期表（含週期表趨勢）：练习题

Which of the following is defined as the sum of the protons and neutrons in the nucleus of an atom?

An atom of an element is represented as \(^{27}_{13}\text{Al}\). Which of the following correctly identifies the number of protons and neutrons in the nucleus of this atom?

Elements in the same group of the Periodic Table exhibit similar chemical properties. Which of the following is the primary reason for this similarity?

Which sub-atomic particle in an atom has a relative mass of 1 and an electrical charge of +1?

The elements in Group 7 of the Periodic Table are known as the halogens. Which statement correctly describes the trend in their physical properties as you move down the group from fluorine to iodine?

What does the atomic number of an element represent in terms of sub-atomic particles?

Explain why the elements in Group 0 of the periodic table, known as the noble gases, are chemically unreactive.

Define the term isotope and explain how \(^{12}\text{C}\) and \(^{14}\text{C}\) differ in their atomic structure.

All substances are made of atoms, which are the fundamental building blocks of matter. An atom consists of a small central nucleus surrounded by electrons.

a) Name the two types of sub-atomic particles that are found in the nucleus of an atom. (2 marks)

b) State the relative electrical charge of a proton and an electron. (2 marks)

Atoms of the same element can have different numbers of neutrons. These atoms are called isotopes.

a) Explain what is meant by the "mass number" of an atom. (1 mark)

b) An atom of Sodium is represented as \(^{23}_{11}\text{Na}\). Determine the number of protons, neutrons, and electrons in this atom. (3 marks)

c) Another isotope of Sodium is \(^{24}_{11}\text{Na}\). State one similarity and one difference between the nuclei of these two isotopes. (2 marks)