Chapter 3 Flashcards
The total mass of a substance does not change during a chemical reaction
Law of mass conservation
A given compound always has the same composition / same amount of ratio of elements
Constant composition
When two elements react to form more than one compound
Law of multiple proportions
Hydrogen and oxygen can combine to create both H2O (water) and hydrogen peroxide (h2o2) is an example of
Law of multiple proportions example
- Elements are made up of atoms
- An elements atoms are identical
- Atoms of an element will differ from other elements.
- Atoms of one element combined with atoms of another element create a compound
- Atoms are indivisible in a chemical process
Daltons atomic theory
Used to study charge particles
Cathode ray tube
Used to find out the charge of an electron
Milligan’s oil drop experiment
The main premise of the Millikan oil drop experiment
The oil droplets with the higher amount of positively charged electrons would sink faster to the bottom
The smallest difference in speeds of oil droplets in Millikans experiment happened
The difference of 1 electron
The 3 key characteristics of an electron
- Negative charged particles
- Very light compared to an atom
- They move rapidly within the atom
The mass of an electron
1/1836th the mass of a Hydrogen atom
The mass of an atom is not due to
Electrons
The atom
A cloud of positive charge with very small particles of negative charge embedded in it
An electron
Negative charge
Alpha particles are
Small positively charged particles
The alpha particles that were reflected in the gold experiment
Hit the nucleus.
*what happened to the the alpha particles when it hit the nucleus
The nucleus has a __ charge?
Positive charge
- a positive charge in the nucleus is what
The center of a atom
The nucleus
Majority of the volume of an atom consists of
Electrons
*electrons are the majority of what
The size of a nucleus
Is very small
*what is very small in a atom?
What is a common expression said about atoms?
That they are empty space
*”made up of empty space” is a common answer to what
Uncharged particles
Neutrons
Neutrons have a mass of __ and a charge of __
*neutrons
1 and zero.
- what has a mass of one and a charge of zero
What is mass?
*mass
The quantity of matter in an object
The structure of the nucleus consists of
*nucleus
Protons and neutrons
*protons and neutrons make up the structure of
2000 times the mass of a neutron
Proton (size)
Charge of a proton
+1
Charge 0
Neutron (charge)
A neutral atom
of protons = # of electrons
This particle defines an element
*it defines it
A proton
*a proton has what relationship with an element
Visualize this in your head - where is the mass number located?
Top left
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The mass number equals
of p + # of n
Visualize this in your head - The atomic number is located?
Bottom left
The atomic number equals
of protons OR # of e for neutral atoms
Electrons are
Negative charged particles in an atom
Isotopes
Atoms with the same number of protons but different number of neutrons
To determine the isotopes
Atomic numbers must be the same
The nucleus is composed of
Positively charged protons and uncharged neutrons
The nucleus is surrounded by
Negatively charged electrons
The mass of an atom is
Derived mainly from the nucleus
Why is the majority of the mass inside of the nucleus
Because protons and neutrons are much heavier than electrons
Go from heaviest to lightest with e,p, and n
Neutrons heaviest, then protons, then electrons which are lightest
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The atomic number
The number of protons in the nucleus is
Defining trait in an element
Number of protons in the nucleus
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Atomic number =
Number of protons
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All atoms have the same __ but can have a different ___
Atomic number; mass number
Isotopes
Atoms with the same atomic number (protons) but not the same mass number (different neutrons)
If you are given the atomic mass and the atomic number how do you find the amount of neutrons
Mass minus the atomic number
Radiation with no electric charge
Gamma rays
Radiation with a negative charge
Beta particle
Radiation with a positive charge
Alpha particles
Weight of alpha,beta, gamma particles
- Heavy weight
- medium weight
- Light weight
Penetrating abilities of particles
Alpha particles can be stopped by thick paper
Beta particles by aluminum foil
Gamma rays by a lead wall
Gamma rays and x rays are forms of
Electromagnetic radiation
Gamma rays in comparison to x rays
Shorter wave length and higher energy
Strong nuclear force
Protons should repel each other in the nucleus. This keeps it together
Electrostatic force
repulsive force between two electrically charged objects
Where do alpha particles come from
When the nucleus becomes to big it becomes unstable and some particles will fall apart
Alpha particle has an elemental nucleus of
Helium
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Alpha particles - protons and neutrons
2 protons and 2 neutrons
Alpha particle is related to which element?
Helium
Alpha decay means
Minus the mass (4) and the atomic number (2) from the element
A beta particle can also be known as a
Electron
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Instead of an atomic number, what would you put for a beta particle?
-1
Mass of a beta particle
0
What happens to the atomic number in beta decay?
It increases
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beta decay increase the atomic number
Neutrons become protons
mass and atomic number for protons
1 and 1
Mass spectrometer
Used to measure isotopes
Average atomic number
Is the average of all the isotopes of an element
The simple version of isotopes
Different versions of an element or a type of atom
Isotopes protons and neutrons
Have the same protons but different neutrons
Calculation of the average atomic mass of an element
Atomic mass x percentage/100
Do that to all them then add all together
ions
atoms or groups of atoms with an electrical charge
two types of atoms
cations
anions
cations
positively charged ions result from losing an electron
anions
negative charged ions resulting from a gain of an electron
neutral atom
protons = electrons
formation of ions
gaining or losing electrons
removing or adding protons
change in element
ions do or do not change the element
do not
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the amount of protons
atomic number
the amount of neutrons
atomic number minus the mass number
the amount of electrons
its the same amount as protons (atomic number) but look if it has an electrical charge
element with a negative in the top right, what does that do to the number of electrons?
adds one electron
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a positive charge on an element tells you what
how many electrons you need to subtract
a negative charge on an element tells you what
how many electrons you need to add
posititve charges or cations are metals t/f
true
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how are the elements organized on the periodic table in relation to their charge
the elements with the same charge are in the same column
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noble gases in relation to their ions
this column does not contain ions on the periodic table
compound
formed when two or more elements combine together in a fixed ratio
3 types of chemical formulas
molecular, structural, emperical
molecular formula
shows the actual composition of a molecule
structural formula
shows the actual composition of a molecule and how the atoms are connected
emperical formula
shows the simplest whole number ratio between the atoms in a compound
stable/unstable: noble gases
very stable
stable/unstable: alkali metals
unstable
3 Properties of non metals
Not shiny, not malleable, poor conductors of heat and electricity
Period and group meaning
Laterally, up and down periodic table
Allotropes
Different forms of the same element in the same state
