Transcript Chemical Elements and atoms - Cuda Anatomy

ANATOMY & PHYSIOLOGY
Chapter 2: Introductory Chemistry
Concepts of Matter
matter
- anything that occupies space and has mass
- may be changed both physically and chemically
physical change
- does not alter nature of substance
i.e.) change in state - ice to water
chemical change
- does change composition of substance
i.e.) fermentation of grapes
Concepts of Matter
states of matter
a. Gas
no definite shape; no definite
volume. i.e.) air
b. Liquid
definite volume; conforms to
shape of container i.e.) blood;
interstitial fluid
c. Solid –
definite shape and volume i.e.) bones
d. Plasma
Chemical Reactions
energy
1. mass-less; does not take up space
2. measured by its effect on matter
3. ability to do work or to put matter into
motion
Chemical Reactions
Energy
All forms of energy (4) exhibit both:
a. kinetic energy
• when energy is moving objects;
actually doing work - causing an
effect
b. potential energy
• inactive or stored energy
Concepts of Energy
4 forms of energy
chemical energy
• energy stored in the bonds of
chemical substances and released
when bonds are broken
electrical energy
• energy resulting from movement of
charged particles
Concepts of Energy
4 forms of energy
radiant energy
• energy that travels in waves; energy
of the electromagnetic spectrum
mechanical energy
• directly involved in putting matter
into motion
Concepts of Energy
energy form conversion
1. energy is easily converted from one form
to another
2. energy conversions are inefficient;
some of the initial energy supply is lost
(unusable) to the environment as heat
?Question?
The statement has been made that “some
energy is lost in every energy
transformation.” Explain the meaning of this
statement.
Is it really lost?
If not, where is it?
Intro to Chemistry
Chemical Elements and atoms
elements
unique substance that cannot be decomposed
or broken down into simpler substances by
ordinary chemical methods
118 (120) discovered elements; 92 occur
naturally; 26 (28) produced artificially
4 different elements make up most of the
body
Chemical Elements and atoms
•
four most abundant (making up
96 % of body’s mass) these elements are
O,C,H & N
• elements that make up approx.
3.8 % include Ca, P, K, S, Na, Cl, Mg, Fe
• trace elements - additional 14 elements present
in tiny amounts make up the balance of
approx. 0.2% -include:
Al, B, Cr, Co, Cu, F, I, Mn, Mo, Se, Si, Sn,
V, Zn
Chemical Elements and atoms
Atoms
a. building block of an element
b. smallest particle that still retains its
specific properties
c. two basic parts: nucleus and one or more
electrons
Chemical Elements and atoms
Atoms
d. an atom is a cluster of smaller
(subatomic) particles and can be split
into these
e. an atom loses the unique properties of its
elements when it is split in its
subparticles
Atomic Structure
subatomic particles
• three basic particles differing in their:
a. mass,
b. electrical charge, and
c. location within the atom
• the electrical charge of a particle is a
measure of its ability to attract or repel
other charged particles
subatomic particles
1. proton – positive charge
2. neutron– neutral charge
3. electron – negative charge
subatomic particles
 all atoms are electrically neutral; the
number of protons must be balanced by the
number of its electrons
 protons and neutrons are clustered at the
nucleus
subatomic particles
 electrons orbit around the nucleus, forming
a negatively charged electron cloud
 most of the volume of an atom is empty
space, and nearly all of the mass is
concentrated in the nucleus
Differentiating elements/atoms
 to identify a particular element:
a. atomic number
• equal to the number of protons its atom
contains
b. mass number
• the sum of the protons and neutrons in
its nucleus
Differentiating elements/atoms
 atoms of different elements are composed of
different numbers of subatomic particles
 again, number of protons and electrons are equal;
number of neutrons vary
 light atoms tend to have equal number of protons,
electrons, and neutrons
 larger atoms have more neutrons than protons and
electrons
Differentiating elements/atoms
isotopes
• atoms of almost all elements exhibit two or more
structural variations called isotopes
1. isotopes have the same number of protons and
electrons, but vary in the number of neutrons
they contain - thus,
2. has the same atomic number (same chemical
properties) of the element, but has a different
atomic mass
3. an element’s lightest isotope is more abundant
than its heavier forms
Differentiating elements/atoms
radioisotopes
• heavier isotopes of certain elements are
unstable and decompose to become more
stable
1. radioactivity – spontaneous atomic decay that
involves:
a. ejection of particles
i. alpha (least penetrating)
ii. beta
b. electromagnetic energy
i. gamma rays (most penetrating)