Chemistry of Life Inorganic Chemistry

What is an element? A Pure substance that contains on one type of atom. There are 92 naturally occurring elements. They are put together in the form of “The Periodic Table of the Elements”

96% of the mass of a human is made up of the following four elements: Carbon (C) Hydrogen (H) Oxygen (O) Nitrogen (N) The one or two letter abbreviation is called the chemical symbol. Sodium (Na) Chlorine (Cl)

What is an atom? An atom is the basic unit of matter. It includes a central nucleus which includes protons and neutrons. Protons have a positive (+) charge and neutrons have a neutral charge.

An electron cloud surrounds the nucleus. It is comprised of energy levels that contain electrons. Electrons have a negative (-) charge.

Each energy level can only hold a certain amount of electrons. 1 st : 2 electrons 2 nd : 8 electrons 3 rd : 8 electrons

Atomic number: # of protons Mass Number: # of protons + # of neutrons Symbol: one or two letters representing the element

Isotope- Same element but with a different number of neutrons Protons stay the same, neutrons change. This means the mass number changes.

Atoms of 2 or more different elements chemically joined together form a compound. Examples of compounds: – Water (H2O) – hydrogen and oxygen bonded together – Table salt (NaCl) – Sodium and chloride bonded together

Covalent bonds share electrons. Example of covalent bonds is water (H2O). Ionic bonds transfer electrons Example of ionic bonds: table salt (NaCl).

Molecule Smallest particle of a substance; it retains its properties through composed of one or more atoms positively (+) or negatively (-) charged. Ion: a charged particle (pos or neg)

Mixture: substances or combined, but each keeps its own properties. Example: saltwater, big mac Solution: mixture of one or more substances (one being dissolved and the other does the dissolving) Solute: substance being dissolved in a solution Solvent: substance doing the dissolving in a solution

Example of parts of a solution: Lemonade=solution Solvent=water Solute=sugar/lemon juice

pH A measure of how acidic or basic a solution is. 1-6 Acidic 7 neutral 8-14 Basic

Acid Below 7, More H+ than OH- Ex: Lemon juice, milk, HCl

Base Above 7; less H+ than OH- Ex: ammonia, drain – o, eggs, soap

Neutral pH = 7; equal amount of H+ and OH- Ex: pure water.

pH scale Ranges from =strongest acid 14=strongest base

Polar molecule Atoms in covalent bond that do not share electrons equally (has positive and negative ends) Typically disolves in H2O. Ex: Water, H2O

Hydrogen bond Weak bond created by a hydrogen atom attracted to oppositely charged atoms Ex: Water, 2 hydrogens (+) + 1 oxygen (-) = H2O

Non-polar molecule Electrons are equally shared by atoms Ex: O2, H2, CH4 (methane)

Characteristics of Water: Water is polar Water resists temperature changes Water expands when it freezes Water is cohesive – it sticks to itself Water is adhesive – it sticks to other stuff Water has surface tension – Ex: a bug walks on water.

Surface Tension Water’s ability to stick to itself. This causes some insects to walk on water, causes rain to form droplets and small objects to float on water. It is a cohesive force between the molecules of water.

Let’s draw an atom… Remember atoms include a nucleus with protons and neutrons. An electron cloud surrounds the nucleus. Using three colors, draw this atom in the empty space in your notes.