Bonding (OCR Gateway GCSE Chemistry)

Covalent molecules can be displayed using a variety of diagrams and written formulae.

Which of the following shows the number of non-bonding electrons present in a molecule?

Ammonia, NH₃, is a small covalent molecule.

How many non-bonding, outer-shell electrons are present in one molecule of ammonia?

Magnesium reacts with element Z to form a compound with the formula MgZ.

Which of the following elements could be Z?

Elements can bond together in many different ways, by sharing, gaining or losing electrons. In some of the resulting structures, strong electrostatic forces of attraction occur as a result of the type of bonding.

Which of the following examples does not involve strong electrostatic forces of attraction?

When atoms gain or lose electrons they can end up having the same electronic structure as other ions or atoms. The nucleus still remains untouched.

Which of the following does not have the same electronic structure as the others in the list?

Different substances have characteristic melting and boiling points, depending on the strength of the bonds or forces holding them together.

Which explains why methane has a lower melting point than sodium chloride?

Element X has the following properties:

• melts at 450^oC
• boils at 1091^oC
• Forms an ion with a 2+ charge

Which is most likely to be element X?

Metals and non-metals commonly have different physical and chemical properties.

Which of the following is a property of metal elements only?

The diagram shows the electronic structure of some elements:

Which of the following does not explain why they would be placed in the same group of the modern Periodic Table?

Polymers are long covalent molecules, often known as 'macromolecules'.

Figure 1 shows a section of a polymer chain.

Figure 1

What is the empirical formula of this polymer?

The positions of some elements in the Periodic Table are shown by the letters A to G.

The letters shown are not the symbols of the elements.

Which elements are in Period 2?

Which substance has ionic bonding?

The electronic structure of an atom of an element is 2.8.8.2.

In which period of the Periodic Table is this element found?

The electronic structure of an atom of an element is 2.8.8.2.

In which group of the Periodic Table is this element found?

Which statement about covalent bonding is true?

Sodium is an element that can be found in the Periodic Table.

A sodium atom contains 11 electrons.

Which statement about sodium is true?

Mendeleev’s arrangement of elements led to our modern Periodic Table.

How did Mendeleev arrange the elements in his Periodic Table?

What is the electronic structure of sulfur?

Which equation shows the formation of a Group 2 metal ion?

M represents a Group 2 metal and e⁻ represents an electron.

Look at the diagram of a methane molecule.

Which statement about methane is correct?

Which of these substances has a giant covalent structure?