chapter 2- water and carbon- the chemical bases of life

Learning objectives

• 2.1- analyze the relationship between atomic structures and how atoms interact in simple molecules

• 2.2- summarize the properties of water and explain how they are necessary for life

• 2.3- explain the changes in bonds, energy, and entropy that occur in a chemical reaction

2.1- atoms, ions, and molecules- the building blocks of chemical evolution

• atom types

  • hydrogen, carbon, nitrogen, oxygen

• what are the physical structures of hydrogen, carbon, nitrogen, and oxygen atoms?

• what are the structures of the simple molecules- water, carbon, dioxide, and others- served as the building blocks of chemical evolution?

• centeral theme in bio- structure affects function

basic atomic structure

• every element except hydrogen has one or more neutrons in its nucleus

• small particles called electrons orbit an atomic nucleus made up of lager paricles called protons and neutrons

• protons have a positive electric charge (+1)

• neutrons are electrically neutral

• electrons have a negative electric charge (-1)

• when the number of protons and the number of electrons in an atom are the same, the chages balalnce and makes the ENTIRE atom electrically neutral

• elements are defined as substances that cinsist entirely of a single type of atom

• each atom of a element has a characteristic number of protons called the atomic number

  • written as a subscript to the left of an elements symbol

• sum of the protons and neutrons in an atom is called its mass number and is written as a superscript to the left of the symbol

• dalto