Transcript Elements and atomic structure

ELEMENTS AND ATOMIC STRUCTURE
Chapter 5.5 – Day 2
The Atom
The smallest part of an element that is representative
of that element.
The nucleus is the central region of the atom that
contains most of the mass and all the positive charge.
The nucleus contains protons (p+) and neutrons (n)
Electrons (e-) occupy the space outside of the
nucleus.
ELEMENTS AND ATOMIC STRUCTURE
The Bohr-Rutherford model of the atom
suggests that atoms are composed of three
types of subatomic particles:
protons
neutrons
electrons
PROTONS (p+)
Are heavy positively charged particles that
are found in a dense positive core of the atom
called the nucleus
The number of protons in an atom is equal to
the element’s ATOMIC NUMBER! (#p)
The number of protons determines what
element it is!
NEUTRONS (n)
Are neutral particles that have about the
same mass as protons and are also found in
the nucleus.
The MASS NUMBER is the mass of an atom
and is equal to the number of protons plus the
number of neutrons in the atom. #p + #n
ELECTRONS (e-)
Are negatively charged particles with almost
no mass that “orbit” the nucleus at different
energy levels, also called orbitals or shells.
The number of electrons in an atom equals the
number of protons, therefore the atoms
charge is neutral.
Atoms
Carbon
Fluorine
Atomic number =6
Atomic number = 9
Mass number =12
Mass number = 19
#p = 6
#p=9
#n= 12 – 6 = 6
#n = 19 – 9 = 10
#e = 6
#e = 9
phosphorus
Bohr Diagrams
Bohr Diagrams can be used to show the arrangement
of electrons around the nucleus.
Electrons are only found in certain “orbits”, “shells”
or “energy levels” around the nucleus.
Where do the electrons go?
Maximum Electrons
Level 1
2 electrons
Level 2
8 electrons
Level 3
8 electrons
Level 4
18 electrons
HANDOUT – 20
MINUTES
Complete the handout by reading pages 185186.
Work with a partner if you like.
Protons
Electrons
Neutrons
Nucleus
Shells
Nucleus
+ ive
- ive
neutral
Same as Atomic Number
Mass Number - Atomic Number
Same as Atomic Number
Neutral
Electrons
2, 8, 8
IONS
An ion (charged atom) in which the
number of electrons is
different from the number of
protons.
The IONIC CHARGE is the
numerical value of the electric
charge with a plus or minus
sign.
Give Handout to show examples.
HOMEWORK
QUESTIONS PAGE 187: 4,5,6abc
Ion Worksheet
Crossword puzzle (review) – hand in
for marks
Quiz tomorrow on Chapter 5.1 and
5.5