Atoms, Elements
Atoms Protons Neutrons Electrons Contain 3 particles
Nucleus Consists of: Neutrons Protons The Neutron What are the characteristics of the particles? No Charge Determines isotope The Proton Positive charge Determines element The Electron Negative charge Participates in chemical reactions Outer shell e - determine chemical behavior
Atoms The number of electronsThe number of electrons Is equal to the number of protons Electrons in space around the nucleusElectrons in space around the nucleus
What is the atomic number? Number of protons Number of protons plus neutrons 13 Al Atomic number Symbol Mass number What is the mass number?
Atomic Number? C atom with Carbon Mass Number? ____ ____ protons ____ protons ____ neutrons ____ neutrons
Helium Atomic Number? ____ Mass Number? ____ He Protons? ____ Neutrons? ____
Biologically Important Elements Oxygen (O) Carbon (C)Hydrogen (H) Nitrogen (N) Trace elements Calcium (Ca) Phosphorus (P) Potassium (K) Sulfur (S) Sodium (Na) Chlorine (Cl) Magnesium (Mg)
Bonds are formed or broken down in chemical reactions Ionic bonding –Atoms losing or gaining electrons to complete their outer shells
Covalent bonding –Sharing electrons
Covalent bonding –Sharing electrons
Covalent bonds can be: Single Double Triple
Water Our cells are composed of 70% – 95% water Water covers 3/4 th of the earth
The electrons in its covalent bonds are shared unequally How are the hydrogen and oxygen atoms bonded together? Hydrogen bonding?Covalent bonding? Creates POLARITY Water
Hydrogen bonding?Covalent bonding? How are water molecules bonded together? The polarity of water results in weak electrical attractions between neighboring water molecules Creates HYDROGEN bonding
An acid What is: – A compound that accepts H+ ions and removes them from solution? A base A pH scale – A chemical compound that donates H+ ions to solutions? – A measure of H+ ion concentration in a solution?
A pH Scale Acidic Basic Neutral pH 7 – Biological range maintained at ~ 6.5 – 7.5 Blood ~ 7.2 – 7.4 [H+] = [OH+]