Unit 1: Chemistry of Life

• Three subatomic particles and their significance

• Types of chemical bonds and interactions and how they form

• Importance of Hydrogen bonding to the properties of water

• Each unique property of water contributes to life on Earth

• Interpret the pH scale

• Changes in pH can alter biological systems

• Importance of buffers in biological systems

The Chemical Contexts of Life

Matter consists of chemical elements in pure form and in combinations called “compounds”

• Matter, anything that takes up space and has mass

• Element, substance that cannot be broken down into other substances by chemical reaction

  • example: gold, cooper, carbon, and oxygen

• Compound, substance consisting of two or MORE elements combined in a fixed ratio

  • example: water (H2O), table salt (NaCI)

• C, H, O, N, 96% of living matters. 25/92 natural elements are known to be essential to life

  • C = Carbon, H = Hydrogen, O = Oxygen, N = Nitrogen

An element’s properties depend on the structure of its atoms

• Atoms, smallest units of an element that retain the property of the element. Unit of life.

  • Made up of neutrons, protons, and electrons.

  • Building blocks of the physical world

• Protons, positively charged particles found in the nucleus of the atom.

  • Positively charged (+) particle

• Electrons, negatively charged particles found in electron shells around the nucleus. Determine the chemical properties and reactively of the element

  • 

    negatively charged (–) particles

  • one of the three primary types of particles within the atom

• Neutrons, particles with NO charge. Found in the nucleus. Their number can vary in a given element, resulting in isotopes.

  • uncharged particles

  • Some atoms have the same number of protons but differ in the number of neutrons in the nucleus. These are called isotopes.

• Isotopes, forms of an element with differing number of enutrons. Same number of protons but different numbers of neutrons.

  • example: 12C and 14 C are isotyopes of carbon. Both have 6 protons, but 12C has 6 neutrons, whereas 14C has 8 neutrons.

• Radioactive isotopes, widely used in medicine for BOTH diagnostic and treatment. Radiometric data uses the rate of decay or half-life of certainisotopes to determine the ages of foissils and rock strata.

• Atomic number, number of protons an element possesses. The number of protons in a nucleus.

• Mass number, an element is the sum of its protons and neutrons.

The Formation and Function of Molecules depend on chemical bonding between atoms