Chapter 2 Flashcards
What are atoms composed of?
- ) Nucleus: contains neutrons and protons
2. ) Electrons orbiting in the cloud
Atoms Mass#=?
protons + neutrons
Atoms atomic #=?
protons
What are the most abundant biological elements?
Carbon, oxygen, hydrogen, nitrogen
Out of the most abundant biological elements what are their valence’s?
C: 4
O: 2
H: 1
N: 3
Valence:
the amount of electrons that are available to pair to complete an atoms octet.
Ionic vs. Covalent bond?
Ionic: one atom steals an electron from anther causing it to take a negative charge and the other atom to take a positive charge thus drawing the two together
Covalent: atoms share electrons and those electrons orbit the joint atoms
When do ionic bonds typically occur?
When there is a large variance in electronegativity.
When do covalent bonds typically occur?
When there is little to no variance in electronegativity between atoms.
Predictability of the electronegativity of four most common biologically abundant elements:
O»N>C=H
Bond dissociation energy?
energy needed to break a bond
potential energy?
the energy released after breaking a bond that is then transformed to a variety of of forms of energy’s.
Describe the bond dissociation and potential energy as a covalent bond becomes more polar?
bond dissociation energy increases and potential energy decreases.
Describe the bond dissociation and potential energy as a covalent bond becomes more nonpolar?
bond dissociation energy decreases and potential energy increases.
Describe Hydrogen bonds?
- when ever a hydrogen bonds with anther atom typically an oxygen atom. ( this is due to the partial negative charge)
- The differing partial charges will attract other atoms to form weak hydrogen bonds.