Unit 1 Lesson 1 The Chemistry of Biology

Proton, Electron, and Neutron Proton – _______________________that make up part of the _____________ of an atom Neutron – ______________________that make up part of the nucleus of an atom Electron – _______________________that encircle the nucleus. ___________________________________ The number of ______________________________________ ______________________________________________________ in a neutral atom.

Periodic Table of Elements

Atomic Weight 1 proton = ___ measure of weight 1 neutron = ___ measure of weight 1 electron = ___ measure of weight So… ______________________________________________________ To find the number of neutrons: ______________________________________________________

Drawing Diagrams Bohr Diagrams Hydrogen Carbon Oxygen Electron Dot Diagrams

Bonding Atoms try to fill their ___________________________________. They do this by either ___________________________________ electrons. Atoms also do this by _______________ with other atoms. Atoms that want to give away electrons will bond with atoms that want to gain electrons. Example: NaCl Na has ____ electrons, ___in its valence shell and wants to give ____ away Cl has ____ electrons, ____ in its valence shell and wants to gain ____ electron

Types of Bonds 1. Ionic Bonds - actually _______________________the electron to its partner. 2. Covalent Bonds – the two atoms ___________________ the electrons. By sharing electrons both atoms will have full valence shells 3. Polar Covalent Bonds – atoms share the electrons ____________________. One atom is much bigger that the other and holds the electron closer giving a ____________________________________________________________________________________ 4. Hydrogen Bonds – polar covalent bonds create molecules that are ___________ _________________________________________ The slight positive H of one molecule is attracted to the slightly negative O of another molecule. This creates a weak bond we call Hydrogen bonds

Examples of Bonds Ionic Bonds Covalent Bonds Polar Covalent Bonds Hydrogen Bonds

Energy There are two types of energy 1. Kinetic Energy – _________________________________ 2. Potential Energy – _______________________________ Energy is stored in ______________ (potential energy) when bonds are ________________, energy is _____________ (kinetic energy) when bonds are ______________, energy is ___________________.

Chemical Reactions Chemical reaction where atoms are joined together or split apart are represented by symbols in equation form. Example: If carbon is burned in the presence of oxygen, it will combine with oxygen to form carbon dioxide. C + O 2  CO 2 What this means is that 1 atom of carbon + 1 molecule of oxygen react or yield to form 1 molecule of CO 2.

Parts of a Chemical Equation 2H 2 + O 2  2H 2 O All the atoms on the left side of the arrow are called the ___________________ (they react together). The atoms on the right side of the arrow are the _______________________ (they are produced). The numbers in front of the letters represent the number of molecules, while the subscripts or smaller numbers are the base and to the right stand for the number of atoms in that particular molecule.