Principles of chemistry：练习题

Calculate the relative formula mass ( \(M_r \)) of magnesium nitrate, \(Mg(NO_3)_2 \).
(Relative atomic masses: \(Mg = 24, N = 14, O = 16 \))

2.3 g of sodium ( \(Na \)) reacts completely with 3.55 g of chlorine ( \(Cl_2 \)) to form sodium chloride ( \(NaCl \)). If the relative atomic mass of Na is 23 and Cl is 35.5, what is the empirical formula of sodium chloride?

Which statement correctly describes the formation of a covalent bond between two atoms?

An atom of element X has 17 protons, 18 neutrons, and 17 electrons. Which of the following statements is true regarding element X?

State the definition of an isotope and provide an example.

Compare and contrast the bonding and structure of a typical metal with a giant covalent structure like silicon dioxide.

Describe the arrangement and movement of particles in a liquid.

The atom is the fundamental building block of all matter, composed of subatomic particles.

(a) Describe the location, relative mass, and relative charge of the three main subatomic particles found in an atom.

(b) An element has an atomic number of 17 and a mass number of 35. Determine the number of protons, neutrons, and electrons in a neutral atom of this element.

(c) Explain what is meant by isotopes, using an example to illustrate your answer. How do isotopes of the same element differ, and how are they similar?

An element X consists of two main isotopes. One isotope has a mass number of 35 and an abundance of 75.0%. The other isotope has a mass number of 37 and an abundance of 25.0%.

(a) State what is meant by the term isotopes in terms of sub-atomic particles. (2 points)
(b) Calculate the relative atomic mass (\(A_r\)) of element X based on the isotopic data provided. Show your working. (2 points)
(c) Element X reacts with element Y (from Group 1 of the Periodic Table) to form an ionic compound. Describe the process of ionic bonding between X and Y in terms of electron transfer and electrostatic attractions. (3 points)
(d) Explain why the compound formed between X and Y has a high melting point. (1 point)