Chemical Bonding - Grade 10

Flashcards covering chemical bonding concepts for Grade 10, including ionic, covalent, and metallic bonds, molecular structures, allotropes of carbon, and factors affecting bond strength.

What is chemical bonding?

Chemical bonding is the attraction between atoms that allows the formation of chemical substances.

What are the three main types of chemical bonds?

Ionic bonds, covalent bonds, and metallic bonds.

What is an ionic bond?

An ionic bond is the electrostatic force of attraction formed when there is complete transfer of electrons between atoms to attain stability, resulting into $2$ oppositely charged ions.

Between which types of elements are ionic bonds generally formed, and what is the exception?

They are generally formed between a metal and a non-metal, except in Aluminium and Chlorine where a metal and a non-metal form a covalent bond.

What type of structure is formed by all ionic compounds?

All ionic compounds form Giant Ionic Structures.

Why do most ionic compounds dissolve in water?

Because they are made of oppositely charged ions that are attracted by the polar water molecules.

Why do ionic compounds have high melting and boiling points?

Because they have a giant ionic structure with strong ionic bonds.

Under what condition do ionic compounds conduct electricity, and why?

They conduct electricity in molten or aqueous state due to the presence of mobile ions.

What two factors contribute to the strength of an ionic bond?

Atomic size (the smaller the atomic size, the stronger the ionic bond) and charge of ion (the higher the charge, the stronger the ionic bond).

What is a covalent bond?

A covalent bond is a bond formed when atoms mutually share valence electrons to attain stability, meaning each of the $2$ bonded atoms contributes one electron to form the shared pair of electrons.

How is a shared pair of electrons represented in a covalent bond diagram?

A pair of shared electrons is represented by a dash (-) and is called a single covalent bond. It can also be a double or triple covalent bond.

What is a dative covalent bond (coordinate bond), and how is it represented in a diagram?

A type of covalent bond where both of the electrons in the shared pair are from the donor atom; in a diagram, it is shown as an arrow pointing at the acceptor atom.

What two structures are associated with covalent bonding?

Simple molecular structures and giant covalent structures.

What are Van der Waal's forces, and what increases their strength?

Intermolecular forces present in all molecules that occur due to opposite charges developing between atoms or molecules; the strength of the Van der Waal force increases as the size of the molecule increases.

What is hydrogen bonding?

An intermolecular force where an electro-positive hydrogen atom is attracted to an electro-negative atom of a neighbouring molecule.

Why are substances with simple molecular structures poor conductors of electricity in both solid and molten states?

In the solid state, they lack mobile ions, and in the molten state, they lack delocalized electrons.

Why do simple molecular structures have low melting and boiling points?

Because their molecules are held by weak Van der Waal forces of attraction.

What are allotropes?

Allotropes are different forms of an element that exist in the same physical state.

Why is diamond a poor conductor of electricity?

All four valence electrons in each carbon atom are used in bonding, leaving no delocalized electrons.

Why is diamond the hardest known substance?

Due to the uniformity of strong covalent bonds between atoms throughout the giant covalent structure.

What are the main uses of diamond and why?

Making jewelry (due to its shiny appearance after polishing) and making drill bits (due to its hardness).

Why is graphite a good conductor of heat and electricity?

Each carbon atom uses $3$ valence electrons in bonding to $3$ other carbon atoms in hexagonal layers, leaving $1$ delocalized electron.

Why can graphite be used as a lubricant and for making pencil lead?

It is soft and slippery with a high melting point, and its hexagonal layers are held by weak Van der Waals forces, allowing them to slide over each other when pressed.

Describe the structure and bonding in Silicon iv Oxide.

Each silicon atom is covalently bonded to $4$ oxygen atoms, forming a giant covalent structure with strong covalent bonds.

What is metallic bonding?

An electrostatic force of attraction between positive ions and delocalized electrons.

How does the number of delocalized electrons vary from Group I alkali metals to Group II and III elements in metallic bonding?

Group I alkali metals have one delocalized electron per positive nucleus, whereas in Group II and III elements there is an increase in delocalized electrons.

Why does an increase in temperature reduce the electrical conductivity of metals?

Because an increase in temperature increases the vibrational energy and resistance, which interferes with the flow of electrons.

What two factors affect the strength of a metallic bond?

Number of delocalized electrons (the more the delocalized electrons, the stronger the metallic structure) and atomic size (the smaller the atomic size, the stronger the metallic bond).