Upgrade to remove ads
Only $2.99/month

Chemistry Ionic and Covalent Compounds

Terms in this set (23)

What state are ionic compounds at room temperature? Why?
Are usually crystalline solid at room temperature because their ions are held together by strong electrostatic forces of attraction.
How are the melting and boiling points of ionic compounds? Why?
Ionic compounds have high melting points and boiling points because the electrostatic forces of attraction between oppositely charged ions are strong and large amount of energy is require to separate the ions.
Can ionic compounds conduct electricity? Why or why not?
Ionic compounds cannot conduct electricity when solid but do so when molten or in aqueous solutions because ions are held in fixed position in solid state. When in molten or in aqueous solutions, the ions are mobile and a flow of charge is possible.
Are ionic compounds soluble in water? Why or why not?
Most ionic compounds are soluble in water because water molecules are polar and attracted to the charged ions in the ionic compound
How are the melting and boiling points of covalent compounds? Why?
Covalent compounds have low melting points and boiling points because the inter-molecular forces of attraction are very weak and less energy is required to break the forces apart.
Can covalent compounds conduct electricity? Why or why not?
Covalent compounds cannot conduct electricity in any state because they do not have mobile ions. They consist of molecules.
Are covalent compounds soluble in water? Why or why not?
Covalent compounds are soluble in organic solvents but not in water because covalent molecules are not readily hydrated by water molecules.
Which has a higher melting point: MgO or NaCl? Why?
MgO has a higher melting point than NaCl because Mg lost 2 electrons to form Mg2+ ions where as Na lost 1 electron to form Na+ ion. The greater the charge on a cation , the greater the electrostatic force of attraction, and hence the higher melting point.
What are polymorphs? What are a few examples?
They are different forms of the same element carbon, having different arrangements and physical properties.
What are allotropes?
They are different forms of the same element, having different arrangements and physical properties.
Why is diamond very hard?
Because each carbon atom is bonded to four other carbon atoms by strong covalent bonds in a tetrahedral arrangement.
Why is graphite soft?
Because the carbon atoms are arranged in a layer structure. In each layer each atom is joined to three other carbon atoms in a hexagonal arrangement. The different layers are held together by weak Vander Waal's forces of attraction and can slide over each other
Why is graphite used a lubricant?
The different layers are held together by weak Vander Waal's forces of attraction and can slide over each other
Can diamond conduct electricity? Why or why not?
Diamond cannot conduct electricity because large number of carbon atoms are joined together by strongly covalent bonds and there are no free electrons to conduct electricity.
Can graphite conduct electricity? Why or why not?
Graphite can conduct electricity because each carbon atom uses only 3 out of 4 electrons for bonding with one free electrons to conduct electricity between each layer
Do diamond and graphite have low or high melting point? Why?
Diamond and graphite have very high melting points because they both have a giant macromolecular structure made up of strong covalent bonds. Large amount of heat energy is require to break apart these strong covalent bonds.
Between diamond and graphite, which has a lower melting point?
Graphite has a lower melting point relative to diamond because graphite has a layer structure and only weak Vander Waal's forces between layers. On the other hand, diamond has only strong covalent bonds that hold the carbon atoms together.
How are ionic bonds formed?
1) Metallic atoms transfer valence electrons to non-metallic atoms forming positive and negative ions
2) These ions achieve stable noble gas configuration
3) Opposite charged ions are held together by strong electrostatic forces of attraction known as ionic bond
How are covalent bonds formed?
1) Covalent bonding occurs between non-metals
2) Electrons are sharing between atoms to attain stable noble gas configuration. Each pair of shared electron forms one covalent bond.
How are metallic bonds formed?
Atoms in the metals are held together by a sea of electrons which move freely among the positive metal ions.
What are physical properties of metals?
Metals are malleable and ductile because the ions can slide over each other
Are metals good conductors of electricity? Why or why not?
Metals are good conductors of electricity in either solid or molten state because of the presence of free electrons available to carry electrical energy.
Do metals have high or low melting and boiling points?
Most metals have high melting and boiling points because of the strong forces of attraction between the sea of electrons and the positive metal ions.
THIS SET IS OFTEN IN FOLDERS WITH...