Bio 311C QUESTIONS AND ANSWERS A+ GRADED
Matter
Anything that has mass and takes up space
element
a substance made up of a single atom that cannot be broken down further
molecule
A group of atoms bonded together
compound
A substance made up of atoms of two or more different elements joined by chemical
bonds
How to calculate mass number
number of protons + number of neutrons
how to calculate molecular weight
add up the individual atomic weights of each element
* unit = g/mol
What are valence electrons?
electrons in the outermost shell
what is the valence of carbon
4
what is the valence of nitrogen
3
what is the valence of oxygen
2
what is the valence of Phosphorus
3
valence of Na
1
valence of Cl
1
valence of H
1
polar covalent bond and example
A covalent bond in which electrons are not shared equally. Example: H2O
nonpolar covalent bond
a covalent bond in which the electrons are shared equally by the two atoms. Ex: O2
Ionic bond and example
A chemical bond resulting from the attraction between oppositely charged ions. Ex:
NaCl
H bonds and example
hydrogen atom that is connected to an electronegative atom is then attracted to another
electronegative atom. 2 water molecules bonding
Van der Waals interactions and example
attractions between molecules that are close together as a result of their charges. non
polar situations. Example: cellulose in cell walls or inside phospholipid tails
Matter
Anything that has mass and takes up space
element
a substance made up of a single atom that cannot be broken down further
molecule
A group of atoms bonded together
compound
A substance made up of atoms of two or more different elements joined by chemical
bonds
How to calculate mass number
number of protons + number of neutrons
how to calculate molecular weight
add up the individual atomic weights of each element
* unit = g/mol
What are valence electrons?
electrons in the outermost shell
what is the valence of carbon
4
what is the valence of nitrogen
3
what is the valence of oxygen
2
what is the valence of Phosphorus
3
valence of Na
1
valence of Cl
1
valence of H
1
polar covalent bond and example
A covalent bond in which electrons are not shared equally. Example: H2O
nonpolar covalent bond
a covalent bond in which the electrons are shared equally by the two atoms. Ex: O2
Ionic bond and example
A chemical bond resulting from the attraction between oppositely charged ions. Ex:
NaCl
H bonds and example
hydrogen atom that is connected to an electronegative atom is then attracted to another
electronegative atom. 2 water molecules bonding
Van der Waals interactions and example
attractions between molecules that are close together as a result of their charges. non
polar situations. Example: cellulose in cell walls or inside phospholipid tails
