Flouride In Water

Fluoride in the Water • Fluoride

Essential Chemistry For Biology

– Is a common ingredient in Earth’s crust – Helps maintain healthy teeth • Fluoride prevents cavities by – Affecting the metabolism of oral bacteria – Promoting the replacement of lost minerals on the tooth surface

SOME BASIC CHEMISTRY • Why chemistry? I thought this was a biology course • Well, take any biological systemapart, and you eventually end up at the chemical level. – Indeed, your body is one big container of chemicals undergoing a continuous series of chemical reactions

Matter: Elements and Compounds • Matter is anything that occupies space and has mass. • Matter is found on the Earth in three physical states: – Solid – Liquid – Gas

Figure 2.1

6

• Matter is composed of chemical elements. –Elements are substances that cannot be broken down into other substances. – There are 92 naturally occurring elements on Earth. • Each element has its own symbol • All of the elements are listed in the periodic table.

C
12
H Li Be g Na Mg K Ca Sc Ti B C N O He F Ne Al Si P S Cl Ar

V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr I Xe

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te

Cs Ba La HfTa W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac Rf Db Sg Bh Hs Mt Uun Uuu Uub
Uuq Uuh Uuo

Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

1

• Twenty-five elements are essential to life. • Four elements make up about 96% of the weight of the human body:
Lead Pb Copper Cu

– Oxygen ( ) yg (O) – Carbon (C) – Hydrogen (H) – Nitrogen (N)

MercuryHg

Figure 2.1

Carbon C: 18.5%

• Trace elements – Occur in very small amounts

Oxygen O: 65.0% Calcium Ca: 1.5% Phosphorus P: 1.0% Potassium K: 0.4% Sulfur S: 0.3% Sodium Na: 0.2%   Chlorine Cl: 0.2% Magnesium Mg: 0.1% Trace elements: less than 0.01% Manganese Mn Boron B Chromium Cr Molybdenum Mo Cobalt Co Selenium Se Silicon Si Copper Cu Tin SnFluorine F Vanadium V Iodine I Zinc Zn Iron Fe

– However, they are essential for life – There are 14 of these elements – Examples:
– Iodine (I) – Fluorine (F) – Iron (Fe)

Hydrogen H: 9.5% Nitrogen N: 3.3%

Figure 2.2

• Iodine is an essential ingredient of hormone produced by the thyroid gland (in the neck) • Iodine deficiency causes goiter.

• Elements can combine to formcompounds. – Compounds are substances that contain two or more elements in a fixed ratio. – Common compounds include p – NaCl (table salt) – H2O (water)

Figure 2.3

2

Atoms • Each element consists of one kind of atom. – An atom is the smallest unit of matter that still retains the properties of an element. • Atoms are composed of subatomic particles. particles – A proton is positivelycharged. – An electron is negatively charged. – A neutron is electrically neutral.
Figure 2.4
Nucleus Cloud of negative charge 2 electrons 2 2 2 Protons Nucleus Neutrons Electrons

• Most atoms have protons and neutrons packed tightly into the nucleus. – The nucleus is the atom’s central core. – Electrons orbit the nucleus.

• Elements differ in the number of subatomic particles in theiratoms. – The number of protons, the atomic number, determines which element it is. – An atom’s mass number is the sum of the number of protons and neutrons. – Mass is a measure of the amount of matter in an object.

Isotopes • Isotopes are alternate mass forms of an element. – They have the same number of protons and electrons, but a different number of neutrons. • The nucleus of a radioactiveisotope decays, giving off particles and energy. • Radioactive isotopes have many uses in research and medicine. – They can be used to determine the fate of atoms in living organisms. – They are used in PET scans to diagnose heart disorders and some cancers.

3

• Uncontrolled exposure to radioactive isotopes can harm living organisms by damaging DNA. – The 1986 Chernobyl nuclear accident...