Elements and Compounds Pt 1 (lecture 3) Flashcards
A compound is made up of
2 or more atoms of different elements joined by bonds
the # of protons determines
an atoms identity
An atoms electron distribution determines
its ability to form bonds
A compounds properties depends
on its atoms and how they bond together
Organisms are composed
of matter
matter is
anything that takes up space and came be weighed
matter is made up of
elements
an element is
a substance that cannot be broken down to other substances by chemical reactions
a compound is a substance
consisting of two or more elements in a fixed ratio
A compound has characteristic (emergent properties) different
from those of its elements
About 20-25% of 92 natural elements are
required for life (essential elements)
Carbon, hydrogen, oxygen and nitrogen make up
96% of all living matter
Trace elements are required/essential
by an organism in only minute quantities (they make up less than 0.01% of mass)
An atom is the
smallest unit of matter that still retains the properties of an element
Atoms are composed of
subatomic particles (electrons, neutrons, protons)
Electrons have a
negative charge (neglagable mass of about 0 dalton)
they are so small that they are ignored when calculating the total mass of the atom
Neutrons have
no electrical charge (a mass of about 1 dalton)
Protons have
positive charge (mass of 1 dalton)
Neutrons and protons form
the atomic nucleus
Electrons form a
“cloud” of negative charge around the nucleus
An elements atomic # is
the number of protons in the neucleus
an elements mass number is
the sum of protons plus neutrons in the nucleus
Isotopes are
two atoms of an element that differ in the # of neutrons
EX: Protieum (hydrogen 1) 1proton, 1electron, 0neutron
Detirium (hydrogen 2) 1proton, 1electron, 1neutron
radioactive isotopes decay
spontaneously, giving off particle and energy
Some applications of radioactive isotopes in biological research are
dating fossils, tracing atoms through metabolic processes, diagnosing medical disorders, half life
Half life is when a parent isotope decays to
a lower state or daughter isotope
energy is the
capacity to cause change
Potential energy is the energy that matter possesses
because of its location or structure
matter has a natural tendency to move
toward the lowest possible state of potential energy
Some elements can satisfy each other
and fill each others valance shells, which is why they react well together
the number of electrons depends
on how reactive they are and what drives them is the satisfaction of filling the shell
the spin of electrons must be
opposite
An orbital is the
three dimensional space where an electron is found 90% of the time
Each electron shell consist
of a specific number of orbitals
no more than 2 electrons can
occupy a single orbital, and that is why they must have opposite spins
