18 Questions
What type of bond is formed when atoms share two electrons?
Single covalent bond
Which molecule has a double bond between its oxygen atoms?
Oxygen (O2)
What shape is the molecule of ammonia?
Pyramidal
Which statement is true about the properties of covalent compounds?
Mostly gases, liquids, or gases made up of molecules
What term is used to describe two different atoms of the same element?
Allotropes
Which of the following is NOT an allotrope of carbon?
Silicon
What type of ions do non-metals form?
Negative ions
In ionic compounds, why do positive and negative charges need to add up to zero?
To ensure stability and no overall charge
What property allows ionic compounds to conduct electricity?
Presence of free-moving ions
Which type of compound has a regular arrangement of alternating positive and negative ions?
Ionic compound
How are covalent bonds formed?
By sharing electrons
What allows covalent compounds to exist in the form of molecules?
Sharing of electrons
Why can't diamond conduct electricity?
Because each carbon atom has four outer electrons
What property makes graphite a good conductor of electricity?
Presence of a free electron per carbon atom
Why are metals usually malleable and ductile?
Their layers can slide over each other
Why do metals have high melting points compared to other materials?
Metals form strong metallic bonds in a lattice
What makes ionic bonding different from metallic bonding?
Ionic bonding involves free electrons, while metallic bonding involves ions
If a material has a lattice structure held together by strong covalent bonds and cannot conduct electricity, which type of material could it be?
Diamond
Study Notes
Covalent Bonds
- A covalent bond is formed when atoms share two electrons, typically between two non-metal atoms.
- Covalent bonds allow molecules to exist.
Molecular Structure
- Ammonia (NH3) has a trigonal pyramidal shape.
Properties of Covalent Compounds
- Covalent compounds do not conduct electricity because they do not have charged particles (ions).
Ions and Isotopes
- Non-metals typically form anions (negatively charged ions).
- Isotopes are different atoms of the same element.
Ionic Compounds
- In ionic compounds, the positive and negative charges must balance to zero to maintain neutrality.
- Ionic compounds can conduct electricity because of the movement of ions.
- A crystalline solid with a regular arrangement of alternating positive and negative ions is known as an ionic crystal.
Allotropes of Carbon
- Diamond is an allotrope of carbon that cannot conduct electricity due to its rigid structure.
- Graphite, another allotrope of carbon, is a good conductor of electricity due to the delocalization of electrons in its planar structure.
Properties of Metals
- Metals are usually malleable and ductile due to the free movement of electrons.
- Metals have high melting points compared to other materials because of the strong bonds between atoms.
Bonding Types
- Ionic bonding differs from metallic bonding in that ionic bonds involve the transfer of electrons, whereas metallic bonds involve the delocalization of electrons.
Material Properties
- A material with a lattice structure held together by strong covalent bonds that cannot conduct electricity could be a covalent network solid, such as diamond.
Test your knowledge on the properties of diamond and graphite, two different forms of carbon with unique characteristics. Learn about the hardness, melting point, and conductivity of these substances.
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