For example, in vertebrates (animals with backbones) the element iodine is necessary ingredient of hormone production by the thyroid gland. A daily intake of .15 milligrams of iodine is adequate for normal activity of the human thyroid, but an iodine deficiency in the diet causes the thyroid gland to grow to abnormal size, producing a deformity called a goiter
Matter – anything that takes up space and has mass;composed of elementsElements – composed of chemically identical atoms • bulk elements – required by the body in large amounts • trace elements – required by the body in small amountsAtoms – smallest particle of an element that still behaves like the element
Molecules – particle formed when two or more atoms chemically combineCompound – particle formed when two or more atoms of different elements chemically combineMolecular formulas – depict the elements presentand the number of each atom present in the molecule H2 C6H12O6 H2O 2-7
Example CaCO3 1 calcium atom (one understood) 1 carbon atom (one understood) 3 oxygen atoms (3 subscript)
Structural formulas show how atoms bond and arearranged in various molecules
SPONCH- Are the main elements of life 97% of the elements in living things Sulfer Phosphorus Oxygen Nitrogen Carbon Hydrogen
20 elements that are found in small amounts Play important roles in the body’s processes I, Zn, Cu, B, Mn , F, Mg, Na, Ca, K,Fe.
Contains the mass of the atom ˙ Protons (p+) which are positive particles ˙ 1 proton = 1 AMU (Atomic Mass Unit) ˙ Neutrons (no) which are neutral particles ˙ 1 neutron = 1 AMU
Electrons (e-) which are negative particles orbit outside of the nucleus - electrons have so little mass that it isn’t measured
Atomic Number – Represents the # of protons in an element Determines the element and its properties #protons + = #electrons - What is overall charge on an atom?
Sum of all protons & neutrons in an atom’s nucleusExample – Sodium (Na) mass number = 23 atomic number = 11. How many protons? How many neutrons? How many electrons?
atoms of an element w/the same # of p+ but a different # of no. It changes the atomic mass C12 = 6 p+, 6 n0, 6 e- 12 AMU C13 = 6 p+, 7 n0, 6 e- 13 AMU C14 =? _?_ AMU
Some isotopes are unstable and decay over time Breakdown and release radioactive particles and energy as radiation to become stable form of another element Ex = C14 becomes N14 Biological uses of Radioactive Isotopes - carbon dating – find the age of bio material - molecular tracers – used to trace reactions in living things - nuclear medicine – imaging and cancer
Charged Atom – Atoms can gain or lose electrons to become charged Anion - an element which gains electrons giving it more electrons than protons anions have a ________?__________charge Cation - an element loses electrons, giving it more protons than electrons cations have a __________?________ charge
Electrons that are found on the outer most orbital. An atom can have 2e- first orbital 8 e- second orbital 18 e- third orbital The octet rule - Atoms are most stable with 8 valence electron
The Octet Rule - Atoms are most stable with 8 valence electrons - To become stable, atoms can:give away electrons to other atoms accept electrons from other atomsshare electrons with other atoms
Chlorine has 17 electrons 2 in the first orbital 8 in the second orbital 7 in the third orbital How many valence electrons does it have? How many more does it need to be stable? Should it gain or lose electrons? What is its ionic charge?
Sodium has 11 e- 2 e- in the first orbital 8 e- in the second orbital 1 e- in the third orbital How many valence electrons does it have? How many valence electrons does it need? Is it easier to gain 7 or lose 1? What is sodium’s ionic charge?
Atoms with 1,2 or 3 valence electrons usually give away electrons and become positive ions (cations) Atoms with 4 valence electrons can either give away or gain electrons Atoms with 5,6, or 7 valence electrons usually gain electrons and become negative ions (anions)
Occur when atoms share e- Nonmetal + nonmetal Strong bonds atoms can share up to 3 pairs of electrons Two types - nonpolar covalent bond: atoms share e- evenly - polar covalent bond: atoms share e- unevenly
One atom holds electrons longer - atom has a slight neg. charge Other atom holds electrons less - atom has a slight pos. charge Creates a molecule with charged poles Water is a polar covalent molecule - gives water its important properties
A weak attraction between polar molecules Positive pole of one molecule is attracted to the negative pole of another Found between H2O Join DNA strands help give proteins molecules their shape
Composed of ions (charged atoms) - remember ions give away or accept electrons to get a complete valence shell Occur between metals and non metals Metal donates electron(pos charge) + nonmetal accepts electron (- charge) = zero charge Opposite charges attract – atoms join and create a new compound
How do you bond potassium and oxygen First determine their charges K+1 O –2 Then criss cross the number (not the sign) and the number becomes the subscript.
K+1 O-2 The final answer is K2O(the one is understood behind O)
Atoms either join with another atom or switch partners The making or breaking of bonds involves changes in energy - in living things, these energy changes can be stored, used to do work or released Law of Conservation of Matter - during chemical reactions matter is neither created or destroyed
Chemical Equation – represents the chemical reaction Fe2O3 + 3H2 2Fe + 3H2O Reactants Products According to the Law of Conservation of Matter, the equation must be balanced - the number of atoms of each element must be equal on each side of the equation
How many elements can carbon bond with? How many electrons does carbon have? How many valence electrons does carbon have? How many MORE electrons does carbon need to have a full outer orbital?