Chapter 2- Chemistry of Life Flashcards
Matter
any material that takes up space
Energy
the ability to do work. In this context, work means moving matter.
Element
A pure substance that cannot be broken down by chemical means into other substances
Periodic table
Table the arranges the elements in such a way that their chemical properties repeat in each vertical column
Bulk elements
elements that are needed in the largest amounts because they make up majority of every living cell
Trace elements
elements that needed in small amounts
Atom
the smallest possible “piece” of an element, that retains the characteristics of the element
Three types of particles
Protons: carry a positive charge
Neutrons: uncharged
(Protons+Neutrons create the central nucleus)
Electrons: carry a negative charge
Atomic number
the number of protons in the nucleus
Ion
An atom (or group of atoms) that has gained or lost electrons and therefore has a net negative or positive charge. They also form ionic bonds
If # of protons= # of electrons, then atom of electrically neutral; no net charge
Mass number
The total number of protons and neutrons in its nucleus
Isotope
Any different forms of a single element
Atomic weight
Average mass of all atoms of an element; typically, close to the mass number of the most abundant isotope
Radioactive isotopes
Emit energy as ray or particles when they break down into more stable forms. Have a half-life, which is the time it takes for half of the atoms to emit radiation, or “decay” to a different, more stable form.
Compound
a molecule composed of two or more different elements. Written in terms of a molecular formula, where the constituent elements are written with subscripts of the number of atoms of each elements ex. H20