Chapter 31-Chemical Bonding Flashcards
What are the atoms in a molecule held together by?
By forces of attraction called chemical bonds.
What type of elements are unreactive and why?
Elements that have eight electrons in their outer orbit (noble gases) are very unreactive because they are very stable and difficult to change.
What is the octet rule?
When bonding occurs, atoms try to have eight electrons in their outer orbit. (Not a strict chemical law.)
Why does chemical reaction take place?
So that the elements can obtain stable electron arrangement.
What are the exceptions to the octet rule?
Helium, hydrogen and lithium.
What is a molecule?
A molecule is a group of atoms joined together. It is the smallest particle of an element or compound that can exist independently.
What is a covalent bond?
A covalent bond is a bond that consists of shared electrons.
When is a single bond formed?
Single bond is formed when one pair of electrons is shared.
When is a double bond formed?
A double bond is formed when two pairs of electrons are shared.
What is an ion?
An ion is a charged atom or a group of atoms.
What is an ionic bond?
An ionic bond is the force of attraction between positive and negative ions in a compound.
Give two examples of ionic compounds.
Sodium chloride.
Magnesium oxide.
Name the properties of ionic compounds.
1) Usually solid at room temperature.
2) Usually have high melting points and high boiling points.
3) Usually dissolve in water.
4) Usually conduct electricity when molten or when dissolved in water.
Name the properties of covalent compounds.
1) Usually either a liquid or a gas at room temperature.
2) Usually have low melting points and boiling points.
3) Many do not dissolve in water.
4) Do not conduct electricity.
