Covalent Bonding - exam practice
Covalent Bonding
Question 1 of 7
The 'dot and cross' diagram below represents a molecule of ammonia.
What is the chemical formula of ammonia?
What type of bond is present in a molecule of ammonia?
Explain how these bonds are formed.
Hydrogen halides are important chemicals.
The diagram below represents a molecule of hydrogen fluoride.
The diagram above is a 'dot and cross' diagram.
What type of particles are represented by dots and crosses?
What type of chemical bond holds the atoms in the hydrogen fluoride molecule together?
Predict the physical state of hydrogen fluoride at room temperature and pressure.
Explain your answer.
Methane, CH4, is a simple molecule.
Draw a 'dot and cross' diagram to represent a molecule of methane, CH4.
(You may need a periodic table)
The bonds in a methane molecule are covalent bonds.
What is a covalent bond?
Which one of the statements below about the properties of small covalent molecules is correct?
Nitrogen is an element in group 5 of the periodic table.
How many electrons does nitrogen need to gain in order to achieve a noble gas electron configuration?
The displayed formula of nitrogen gas, N2, is shown in the image below.
What does each single line represent in the formula above?
Draw a 'dot and cross' diagram to show the bonding in a molecule of nitrogen gas.
Images A to E show different ways of representing a methane molecule.
Describe what information can be obtained from each representation.
Include the limitations of these representations in your answer.
The table below is missing certain pieces of data.
Complete the table by filling in the blank spaces.
(You may use a periodic table)
Glass is made from silicon dioxide.
Describe the structure and bonding in silicon dioxide.
Silicon dioxide has a very high melting point.
Other substances are added to silicon dioxide to make glass.
Glass melts at a lower temperature than pure silicon dioxide.
Suggest why.