Chapter 2 - The Chemical Basis of Life Flashcards
anything that occupies space and has mass
matter
amount of matter in an object
Mass
gravitational force acting on an object of a given mass
weight
international unit for mass
kilogram (kg)
simplest type of matter, having unique chemical properties
element
About 96% of the body’s weight results
from the elements __
oxygen
carbon
hydrogen
nitrogen
majority of the body’s weight is from __, it is also the most abundant element in the earth’s crust
oxygen (65%)
plays an especially important role in the chemistry of the body, due in part to
its propensity to form covalent bonds with itself and other molecules
carbon
(T/F) Elements can have multiple roles
and exist in different states in the body.
true (ex. mineralized calcium contributes to the solid matrix of bones, while dissolved calcium helps regulate enzyme activities and nervous system signaling)
the smallest particle of an element that has the chemical characteristics of that element.
atom
composed of atoms of only one kind
element (ex. element carbon is composed of only carbon atoms)
(T/F) Atoms are composed of subatomic
particles, some of which have an electrical charge.
true
three major types of subatomic particles
neutrons
protons
electrons
has no electrical charge
neutron
has one positive charge
proton
has one negative charge
electron
Things to remember:
- The positive charge of a proton is equal in magnitude to the negative charge of an electron.
- The number of protons and the number
of electrons in each atom are equal - Individual charges cancel each other, therefore, each atom is electrically neutral.
what forms the nucleus at the center of the atom?
Protons and neutrons
what moves charge moves around the nucleus?
Electron
accounts for 99.97% of an atom’s mass but only 1 ten-trillionth of its volume
nucleus
Most of the volume of an atom is occupied by
electrons
region where electrons are most likely to be found
electron cloud
equal to the number of protons in each atom
atomic number (because the number of electrons is equal to the number of
protons, the atomic number is also the number of electrons
there are how many naturally occurring elements?
90