Chapter 2 The Chemical Basis Of Life Flashcards
What is an element?
A substance that cannot be broken down to other substances by ordinary chemical means
What is matter
Anything that occupies space and has mass
What are the 4 major chemical elements that make up living organisms
Oxygen (O), Hydrogen (H), Carbon (C), and Nitrogen (N)
What are trace elements?
Essential elements, but only in minute quantities.
Name the elements that account for 4% of the human body
Calcium, phosphorus, potassium, sulfur, sodium, chlorine, magnesium,
Name at least 5 trace elements
Boron, chromium, cobalt, copper, Florine, iodine, iron, manganese, molybdenum, selenium, silicon, tin, vanadium, and Zinc
What is a compound
A substance containing two or more elements in a fixed ratio
Which are more common: compounds or pure elements?
Compounds
What are the three main subatomic particles and what are their charges?
Proton-positive- nucleus
Neutron-no charge- nucleus
Electron-negative- electron cloud
Atomic number is
Number of protons in an element
An atoms mass number is:
The sum of the protons and neutrons in the nucleus
The atomic mass is
The weight of the atom, approximately equal to the mass number
What is an Isotope
The different isotopes of an element have the same number of protons and electrons but a different number of neutrons. Behave the same in chemical reactions
What is a radioactive isotope and why is it radioactive?
An isotope in which the nucleus decays spontaneously, giving off particles and energy. Some isotopes with more neutrons are radioactive because the neutron stores excess energy that is released as radioactivity
Why are radioactive isotopes helpful?
They can help us when we use them for scans like a PET or MRI because our body cannot distinguish one isotope from another so we can use them as tracers.
How can radioactive isotopes be dangerous?
Radioactivity in larger quantities than given in PET’s are harmful to living organisms and potentially deadly. They damage molecules and DNA
What are electron shells?
Energy levels in which electrons occur. Highest energy she’ll in living organisms has 8 electrons in the shell. Lowest has one in the first shell
What are Chemical Bonds?
Attraction of two atoms to form a bond. 2 types: covalent and Ionic