Ch. 2 Chemical Basis of the Body (pp ) Matter *Basic material of universe *Anything which occupies space and has mass *Mass and weight are different *Mass is the amount of matter something has *Weight is the effect of gravity on something *EX. On the moon your mass would be the same as it is here on Earth but your weight would be different (lighter).

3 Forms of Matter Solid Liquid Gas

Solid Tightly linked Definite shape Vibrate in place

Liquid Not so tight Maintains fix volume Fits container

Gas Loose Fits container Move rapidly

Atoms *Smallest units of matter that have their own distinct properties *Based on these properties, they are classified into elements *109 elements, 92 occur naturally

Elements Body has about elements in it. However, C, H, O and N make up 96% of body mass. Add Ca and P and this makes up 99% of body mass. The rest are in small numbers. O = 65% N = 3% C = 18% H = 10% Ca = 1.5% P = 1.0%

Atomic Structure *Nucleus and electron shell *Nucleus contains protons (+) and neutrons (o). These have about the same mass and make up most of the atom’s mass. *Electron shells (electron orbitals or energy levels) contain electrons (-) which are 1/1800 the mass of a proton. They travel at the speed of light (186,000 m/p/s).

Sub Atomic Particles Protons are positively charged Neutrons are neutral, no charge

Sub Atomic Particles Electrons are negatively charged

Sub Atomic Particles *If the number of protons is the same as the number of electrons in an element then there is no electric charge *When atoms gain or lose electrons they take on an electric charge and become ions. Atomic number is the number of protons, which is the same as the number of electrons in a stable element Atomic mass is the number of protons and number of neutrons together

Sub Atomic Particles protons.html

Molecules *Two or more similar atoms combined *Diatomic molecules are “7 to 9 down to iodine, hydrogen doesn’t rhyme” *When atoms are different, they form a molecule called a compound. EX. Na + Cl  NaCl *They have their own properties which are different than the properties of the individual atoms

Chemical Bonds *When electrons are gained, shared or lost *Invisible force which holds 2 atoms together

Chemical Bonds *Electron shell (2,8,8,etc) or energy level is lowest near nucleus and higher as you come out * The outer shell shows how stable an atom is * If it is full, it is inert and will not react (most stable form). Look at VIII all inert gases *If it is not full, it is reactive and will react to become more stable.

QUSTIONS 1-22 ?

3 Main Types of Chemical Bonds 1. Ionic *Transfer of electrons 2. C ovalent *Sharing of electrons 3. Hydrogen bonds *Only formed among hydrogen atoms

1.Ionic bonds   lectrostatic charge due to opposite charges *Weak charges * EX. NaCl *Drop NaCl in water and it ionizes and forms Na +1 and Cl -1 * Na + is known as a cation and Cl - is known as an anion. Both are important in the body. *Look at bond. Na atomic number is 11 and Cl atomic number is 17

2. Covalent bonds  Sharing of electrons  Stronger bonds EX. H 2 O. Look at bond. H atomic number is 1 and oxygen atomic number is 8.   H single covalent bonds H-O-H *H 2 A single covalent bond H-H *O 2 Double covalent bond O = O

Covalent bonds

3. Hydrogen bonds *Very weak *Formed between hydrogen atoms and a molecule with a weak negative charge *Attractive force is electrostatic

Chemical Reactions *Atoms and molecules react *Bonds broken and formed *New product produced 2 types 1. Synthesis 2. Decomposition

1. Synthesis *Bonds formed *Known as anabolism *Combine atoms, ions, molecules to form larger molecules. Na + Cl  NaCl. The Na and Cl are reactants and the NaCl is the product. *A + B  AB

2. Decomposition Reactions *Bonds broken *Known as catabolism *Break down of molecules into simpler molecules, atoms and ions. AB  A + B

QUSTIONS ?

Health clinic: Clinical use of atomic particles * I sotopes are same atoms but have different number of neutrons *EX. Hydrogen usually has 1 proton and 0 neutrons. This is what water is made from. However, when hydrogen has 1 proton and 1 neutron, it is an isotope called deuterium or heavy water. *Some isotopes are stable and have similar properties like their common atom. *Some isotopes have unstable nuclei *Lose neutrons or protons at measurable rates *These are called radioisotopes

Radioisotopes *By losing subatomic particles, energy is released called radioactive decay. *This energy can penetrate and destroy tissues *Since rapidly dividing cells are more sensitive to destructive effects of radiation, this is why radiation is good on cancer.

X-Rays *Also use radiation *Loss of energy when electrons move from higher electron shell to lower shell *X-rays pass through soft tissue but not bone *Good on teeth and bone *Mammogram: Since tumor is more dense than soft tissue, x-rays are good.

QUESTIONS ?