Download File

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Photoelectric effect wikipedia, lookup

Elementary particle wikipedia, lookup

Introduction to quantum mechanics wikipedia, lookup

Electron scattering wikipedia, lookup

Compact Muon Solenoid wikipedia, lookup

Electric charge wikipedia, lookup

Electron wikipedia, lookup

Atomic nucleus wikipedia, lookup

Transcript
2.1 – Matter
all objects are made of matter
~ something with mass and
volume (remember the density
lab?)
matter can usually be found on
Earth as a solid, liquid, or a gas
atom: building block of all matter
atoms are made up of smaller parts:
proton: particle that has a positive (+)
charge
~ large in size
neutron: particle that has no charge
(neutral)
~ large in size (like a proton)
electron: particle that has a
negative (-) charge
~ very small
~ about 1/1800th the size of a
proton or neutron
atoms have no overall charge
(neutral) because there is an
equal number of protons (+) and
electrons (-)
nucleus: center of atom
~ contains protons and neutrons
electron cloud:
area of space that
surrounds the
nucleus
~ contains the
electrons
electron cloud
nucleus
Happy, happy Carbon atom!
But, are all parts really happy?
element: substance that can’t be broken
down into a simpler form
elements are organized by their
properties on the periodic table
(p.36)
95 naturally occurring elements with
only 8 making up most of Earth’s
crust
element symbols are usually 1 or 2 letters
~ hydrogen = H, carbon = C, oxygen = O
each element has a different number of
protons
~ hydrogen (H) = 1, carbon (C) = 6,
oxygen (O) = 8
number of protons is called the atomic
number of the element
in nature, there can be several versions
of the same element
same number of protons BUT have a
different number of neutrons
~ called isotopes
some isotopes are unstable and give
off neutrons which makes them
radioactive
Hydrogen –
1 P, 0 N
Hydrogen 2 (Deuterium) –
1 P, 1 N
Hydrogen 3 (Tritium) –
1 P, 2 N
radioactive isotope
isotopes of the same element are
shown by writing the symbol and the
mass number
~ H-1, H-2, H-3
mass number: total number of protons and
neutrons in an atom
~ remember those are the two particles
with any measurable mass
~ electrons are too small!
Hydrogen –
1 P, 0 N
H-1
Hydrogen 2 (Deuterium) –
1 P, 1 N
H-2
Hydrogen 3 (Tritium) –
1 P, 2 N
H-3
The NEW Periodic Table
https://www.youtube.com/watch?v=zUDDiWt
FtEM
Read the lyrics to follow along!
compound: substance made from
atoms of 2 or more different
elements
atoms are held together by a force
called a chemical bond
arrangement of electrons determines
how atoms bond together
electrons in the electron cloud are
grouped in different energy levels
each level can hold a limited
number of electrons
outer level can hold 8 electrons
(except for H and He)
~ is stable with outer level full
if the outer level ISN’T full, the atom
will bond with other atoms to get a
total of 8 in the outer shell
sometimes atoms will lose or gain
electrons in order to get a total of 8
electrons in their outer shell
atoms will then have a charge due to
an unequal number of electrons (-)
and protons (+)
~ those atoms are called ions
atoms that lose electrons are positive
ions (more P than e)
atoms that gain electrons are negative
ions (more e than P)
opposite charges attract so an ionic
bond forms between opposite ions,
creating crystalline ionic compounds
covalent bond: when atoms
share electrons to form a
covalent compound
since the number of protons (+) is
equal to the number of electrons
(-), the charge of the molecule is
neutral (no charge)
metallic bond: when atoms share
electrons between many metal
ions
metal ions are positive so are
attracted to the negative electrons
because many ions are sharing many
electrons, metals have unique
properties:
easily shaped (malleable)
drawn into thin wires
conduct heat and electricity