Download Ch 4 – Atoms: Building Blocks of Matter

Ch 4 – Atoms: Building Blocks of Matter
4-2: Structure of the Atom
_____________________________________ : particles smaller than an atom
*Electrons, neutrons, & protons
The Nucleus:
 “core” or center of ________________________
 Contains ______________________ & _______________________
1. ________________________________________ : positively charged particles
* _______________________________ (amu): unit used to measure mass of subatomic particle
*Mass of proton = _______ amu
2. __________________________: electrically neutral particles – NO charge
*Mass of neutron = _____ amu
Atomic Number:
The number of ________________________ determines the type of atom and therefore, what element.
 _______________ _________________: number of protons in the nucleus
*Identifies the element
Ex: Hydrogen = ______ proton
Oxygen = _____ protons
Rev. 3/26/12
Carbon = ______ protons
Nitrogen = ______ protons
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Ch 4 – Atoms: Building Blocks of Matter
Isotopes:
 The number of ____________________/atomic number of an element will never change
 The number of ___________________ can change!
______________________________: atoms of the same element that have the same number of
protons, but different numbers of neutrons
Ex: Hydrogen:
Isotopes: a. Protium = 1 p 0 N
b. Deuterium = 1 p 1 N
c. Tritium = 1 p 2 N
Mass Number and Atomic Mass:
 _________________ __________________ : the sum of the protons and neutrons in its
nucleus
Ex: Carbon:
Isotopes: a. 6 p + 6 n = 12 called C-12
b. 6 p + 8 n = 14 called C – 14
*To determine how many ___________________________ - look at the atomic number and its mass
number
Take : ______________ number - ____________ number= # of neutrons
Formulas:
 p + n = __________ ___________________
 Mass number - # of protons = # of __________________________
* ___________________ ________________ : the average mass of all the isotopes of that
element as they occur in nature.
Rev. 3/26/12
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Ch 4 – Atoms: Building Blocks of Matter
The Electrons:
 ___________________: negatively charged particles
*________________ of electron = 1/1836 amu
 An uncharged atom means the # of __________________ = the # of
___________________ the total charge is __________________ = neutral
 Electrons do not travel on a fixed path around the ______________________.
 _____________________ ___________________: the entire space that electrons occupy
 __________________ _________________: the most likely location in an electron cloud
in which an electron can be found

________________ the energy , the closer the electron to the nucleus

________________ the energy, the farther away
 Each _______________ level can only hold a certain number of __________________.

1st level = max of 2 electrons

2nd level = max of 8 electrons

3 rd level = max of 18 electrons
 Electron arrangement gives an element its 1___________________ properties and
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ability to ________________ to other elements

_____________ : particle that makes up all other known particles in the nucleus
of an atom.
*There are different kinds of quarks
*3 types of quarks = neutron
*3 types of quarks = proton
*Properties called “ ______________________ “ (6) and “______________” (3)
Rev. 3/26/12
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Ch 4 – Atoms: Building Blocks of Matter
4-3 : Forces Within the Atom
Four Forces that account for the behavior of subatomic particles:
1. __________________________ _____________: force of attraction or repulsion
between particles in an atom.
*Similar charges = _______________________________ (proton+proton)
*Opposite charges = ____________________________ (proton+electron)
*Electrons kept in orbit around nucleus due to attraction between
_____________________+_________________________.
2. ____________________ ___________________: force that binds protons and neutrons
in nucleus
*glues protons together to form _________________
* strongest of all four forces, but limited range
3. ____________________ ________________: key to the power of the sun & is
responsible for radioactive decay
*radioactive decay - ___________________ changes into a proton & an electron
4. ____________________: the force of attraction exerted between all objects in nature
*weakest of all forces
Rev. 3/26/12
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