Atoms, elements and compounds：练习题

Which property is characteristic of simple molecular covalent compounds?

An element is located in Group VI of the Periodic Table. Which statement correctly describes the ion it is most likely to form?

The diagram represents the covalent bonding in a molecule of ethene, \(C_2H_4\). In this molecule, how many electrons are shared in total between the two carbon atoms?

Which subatomic particle is correctly described in terms of its relative mass and location within the atom?

Iodine ( \(\text{I}_2\) ) is a simple molecular substance. Which set of properties is characteristic of simple molecular structures?

An atom has a proton number of 7. State its electronic configuration and identify which group of the Periodic Table it belongs to.

Explain why sodium chloride (an ionic compound) generally dissolves in water, whereas many covalent compounds like paraffin wax do not.

Chlorine exists as \( \text{Cl}_2 \) molecules. Describe the bonding in a chlorine molecule and explain why chlorine has a very low boiling point (\( -34^\circ\text{C} \)).

A student is learning about the different classifications of chemical substances: elements, compounds, and mixtures.

(a) Define the terms element and compound.

(b) State the key difference between a compound and a mixture, in terms of chemical composition and ease of separation.

(c) Give one example of a common element, one example of a common compound, and one example of a common mixture found in everyday life.

Water ( \( \text{H}_2\text{O} \) ) is a compound that exists as a simple molecule.

(a) Outline the steps involved in the formation of a covalent bond between two atoms.

(b) Oxygen (O) has 6 electrons in its outer shell and Hydrogen (H) has 1 electron in its outer shell. Explain, in terms of electron sharing, how one molecule of water ( \( \text{H}_2\text{O} \) ) is formed, ensuring all atoms achieve a noble gas electronic configuration.

(c) Explain why, despite being formed from ions, the formula of the compound Zinc(II) Chloride is written as \( \text{ZnCl}_2 \) and not simply \( \text{ZnCl} \) .