How do covalent bonding hold molecules together?
Both atoms are trying to attract same electrons. Force of attraction that each atom exerts on the shared electrons is what holds the two atoms together
(Define) Element’s mass number
Total number of protons and neutrons in an atomic nucleus
(Define) Atomic number
The number of protons in the nucleus of an atom, which determines the chemical properties of an element and place in the periodic table.
Why is carbon important?
Key component for all life (to live, grow, and reproduce). Main element in organic compound. Has 4 valence electrons
Water properties:
- Cohesion/adhesion
- surface tension
- Water denser as a liquid than a solid
- high capacity for absorbing energy
What makes water a great solvent?
Because it is capable of dissolving a variety of different substances. [Polar, owing partial H:positive charge & O:negative]
What determines if a reaction is spontaneous?
- When the product molecules are less ordered than the reactant molecules.
- If the product have lower potential energy than the reactants.
[chemical reactions are spontaneous if they are able to proceed on their own without added energy]
What determines if the reaction is exothermic?
“Outside heating” releases heat (gas to liquid)
What determines if a reaction is endothermic?
“Within heating”. Heat is absorbed during the process (liquid to gas)
(Define) Energy:
The capacity to do work or to supply heat
(Define) potential energy:
Stored energy [called chemical energy, when stored in chemical bonds]
(Define) kinetic energy:
Energy of motion [called thermal energy in molecular motion]
(Define) hydrophobic:
Substances that do not interact w/water [water fearing]
(Define) hydrophilic:
Substances that interact w/water (water loving)
Stanley Miller Experiment:
- hypoth. that life originated from basic molecules from early earth
- idea that gases from atmosphere and sea were stimulated by lighting to produce chemicals for organisms
(Define) functional groups:
Particular spatial arrangements of atoms that have predictable chemistry [how they are going to behave]
Amino and Carboxyl functional groups:
Animo groups function as bases; Carboxyl groups act as acids. Tend to attract/drop a proton, when in solution
Phosphate groups:
Carry two negative charges
Sulfhydryl groups:
Consists of a sulfur atom bonded to a hydrogen atom
Atomic structure:
- sm particles(electrons) orbit an atomic nucleus.
- nucleus: protons & neutrons
(Define) isotopes:
Forms of an element w/different numbers of neutrons
Bonding in terms of valence shell electrons:
The outermost shell of an atom, where unpaired electrons move around, and overlap between two atomic orbitals
(Define) electronegativity:
The ability of an atom to attract shared electrons (how much electrons want to be around that element)
(Define) polar covalent bond:
- A bond in which the two atoms have different electronegativities, causing a separation of charges.
- are asymmetrical
- other elements want to be around it
