Periodic Table
By what particle is the P.T. organized?
proton
H has 1 proton
He has 2 protons... and so on
How many protons in Na sodium with
atomic number=11
mass number=23
11 protons
11 electrons
12 neutrons
What ion makes up the pH scale of acids and bases?
H+ hydrogen ion
What is an isotope?
An element with too many or too few neutrons OR an element with a different mass number.
e.g. C-11 or C-13
What is a compound?
A pure substance that has 2 or more elements chemically bonded together in a formula
e.g. CO2, H2O
C, N, O, H, P, S are metals or nonmetals?
Nonmetals
What element makes up most of the body by mass?
Oxygen- 60%
What is a cation?
positive ion e.g. Na+
What is a radioisotope?
An isotope that is unstable and breaks apart, emitting dangerous gamma radiation. e.g. C-14
What type of compound do nonmetals from?
Molecules
What is a period?
row on the P.T.
What is the definition of an element?
A pure substance with only one type of atom.
e.g. oxygen O2, or sodium Na
What is an anion?
negative ion e.g. Cl-
In what 2 types of imaging are radioisotopes used?
CT or PET (nuclear imaging) scans.
What type of bonding do molecules do?
Covalent bonding or sharing or electrons.
Which side of the periodic Table loses electrons easily in bonding?
RHS -the metals
How many electrons are in a complete first energy level of the electron cloud?
2 electrons: all elements with one energy level want to have 2 electrons in that level; elements will react to get 2 electrons in the outer shell.
e.g. Li (Lithium) has 3 electrons so it will lose 1 electron in order to have a complete first energy level.
What is the definition of an ion?
a charged atom OR
an active form of an element ready for bonding OR
an element with too few or too many electrons
Why is long exposure to high energy electromagnetic radiation such as UV or gamma radiation harmful?
Can damage DNA and cause cancer.
What type of bonding occurs in a salt such as NaCl which is a metal and nonmetal bonded together?
Ionic bonding- transfer of electron(s) from the metal to the nonmetal
How can we tell the ion charge (oxidation number) using the groups I A to VIIIA on the P.T.?
IA 1+ 5A 3-
2A 2+ 6A 2-
3A 3+ 7A 1-
4A 4+, 4- 8A 0
How many electrons make up a complete energy level in the second level and beyond of the electron cloud?
8 electrons: all elements want to have 8 electrons in the second energy and subsequent energy levels, so elements will lose or gain electrons to get that.
e.g. oxygen has 6 electrons and it wants 2 more to get eight. Charge is 2- on Group VI element.
What is an electrolyte?
A salt which, when dissolved in water, breaks into ions and conducts electricity.
e.g. NaCl-table salt- which breaks into Na+ and Cl-
Why do we use radioisotopes with short half-lives (decay time for half of chemical) for diagnosis and treatment of diseases.
So it doesn't stay in the body and cause damage to cells.
The DNA strands are bonded together by what type of bond-covalent(strongest), ionic (weaker) or hydrogen (weak) bonds?
Hydrogen bonds, so the strands can easily break apart for replication or transcription.