Chemistry 101 Flashcards
Why is chemistry important to biology?
life -> cells -> molecules -> atoms
What does the atomic number mean?
numbers of protons and number of electrons
How do you know how many neutrons there are?
mass number - atomic number
What are isotopes?
a different form of a single element when an element has different number of neutrons
What are four types of atoms that make up 96% of all living matter?
H, C, N, O
What can a periodic table tell you about electrons?
electrons exist at energy level and form shells around nucleus
When are atoms most stable?
when their valence shells are full
What is a cation?
losing electrons
What is an anion?
gaining electrons
What is electron transfer?
when an atom donates or gains electrons
What is the octet rule?
8 in outermost shell
What type of bonds do ions form?
ionic bonds
What is electronegativity?
ability of an atom to attract shared electrons
What does an atom with high electronegativity do?
- holds electrons more tightly
- has partial negative charge
- other atom partial positive charge
What is one of the most electronegative of all elements?
oxygen
What are covalent bonds?
sharing electrons
What are two kinds of covalent bonds?
- non-polar
- polar
What are non-polar covalent bonds?
electrons shared equally between atoms
What are polar covalent bonds?
electrons not shared equally between atoms
What are two weak chemical bonds?
- hydrogen bonds
- van der waals interactions
What are van der waals interactions>
weak interactions because of partial charges with electrons moving around
What are the unique properties of water?
- good solvent because of its polarity
- polarity helps water dissolve ions
- slight negative charge attracts positive charges
- slight positive charge attracts negative charges
- dissolves hydrophilic substances
- doesn’t dissolve hydrophobic solutes
What is pH?
measuring the amount of hydrogen protons
What are acidic solutions?
low pH and high H+ concentration
