Introduction to Chemistry Chapter 2

Atoms The smallest component of an element The smallest component of an element Composed of a nucleus made of protons and neutrons Composed of a nucleus made of protons and neutrons Electrons orbit around the nucleus Electrons orbit around the nucleus

Carbon Identify these parts… Electron Proton Neutron Nucleus

Elements Composed of identical atoms Composed of identical atoms Found on the Periodic Table Found on the Periodic Table EX: copper wire, aluminum foil EX: copper wire, aluminum foil

Non-Metals Metals Elements Important to Life

6 Carbon Atomic Number Symbol Atomic Mass Element Name

Chemical Compounds Composed of 2 or more elements bonded in a fixed ratio Composed of 2 or more elements bonded in a fixed ratio Properties differ from those of individual elements Properties differ from those of individual elements EX: table salt (NaCl) EX: table salt (NaCl)

Types of Chemical Bonds Three Types of Bonds Ionic Bonds Covalent Bonds Hydrogen Bonds

Ionic Bonds One or more electrons from one atom are removed and attached to another atom, resulting in positive and negative ions which attract each other.

Covalent Bonds One or more pairs of electrons are shared by two atoms.

Hydrogen Bonds the attractive force between the hydrogen attached to an electropositive atom of one molecule and an electronegative atom of a different molecule.

Biochemistry Biology – Study of life + Chemistry – Study of Matter + Chemistry – Study of Matter Biochemistry – study of chemical processes in living organisms

Organic Chemistry study of compounds containing carbon study of compounds containing carbon Organic Compounds are the basis of all life! Organic Compounds are the basis of all life!

Isotopes Atoms MUST contain the same number of protons! They may have different numbers of neutrons. Therefore atoms of the same element may have different masses. Atoms MUST contain the same number of protons! They may have different numbers of neutrons. Therefore atoms of the same element may have different masses. Example: Carbon-14 vs. Carbon-12 Example: Carbon-14 vs. Carbon-12 Carbon-14 is important for radioactive dating. Carbon-14 is important for radioactive dating.

Calculating parts if an atom: Atomic Number = # of protons Atomic Number = # of protons Atomic mass = # of protons + neutrons Atomic mass = # of protons + neutrons # of neutrons = atomic mass - # of protons # of neutrons = atomic mass - # of protons Neutral atoms: # of Protons = # of Electrons Neutral atoms: # of Protons = # of Electrons

Elements Important to Life Carbon, Hydrogen & Oxygen Carbon, Hydrogen & Oxygen Found in all biomolecules (carbohydrates, lipids, proteins & nucleic acids) Found in all biomolecules (carbohydrates, lipids, proteins & nucleic acids) Carbon has 4 valence (outer) electrons. This allows carbon to bond with up to 4 other elements at one time. Carbon has 4 valence (outer) electrons. This allows carbon to bond with up to 4 other elements at one time. Nitrogen Nitrogen Found in proteins & nucleic acids Found in proteins & nucleic acids Phosphorous Phosphorous Found in nucleic acids Found in nucleic acids Write the information from this slide in the white space of your notes page.