Chapter 2 notes - Chemical basis in life(chapters two and...

Info icon This preview shows pages 1–3. Sign up to view the full content.

Chemical basis in life (chapters two and three) Living things obey the same laws as non-living things do. Element - the substance that cannot be broken down by chemical means - 92 occur in nature if if if if she as - 25 are found in living things - In a human being 96% of total body weight is made up of the elements carbon hydrogen and oxygen and nitrogen - The other 4% are made up of P and 20 others (many are present in trace amounts, which is less than 0.01%) Atom - smallest unit of an element Atoms are composed of: Nucleus - Protons - one unit of positive charge and equal to 1 AMU - Neutrons - no charge and equal to 1 AMU Electrons - Electrons for a cloud around the nucleus - One unit negative charge - 0.0005 AMU (negligible) An atom is electrically neutral, whereas the number of electrons is equal to the number of protons The atomic number is equal to the number of protons The mass number is equal to the number of protons and neutrons and the nucleus Shorthand descriptions of the atoms: 12 C superscript equals mass number 6 C subscript equals atomic number
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

- Atoms of the same element always have the same number of protons, but they could have a different number of neutrons. Isotopes - Atoms of the same element that have a different number of neutrons Radioactive isotopes - unstable nucleus - They decay releasing energy and particles which can be detected -
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.
  • Fall '07
  • BetteDoezema
  • Atom, AMU Electrons Electrons

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern