Chemistry: The Structure of the Atom
Democritus, Dalton, or both? Atoms cannot be destroyed.
both
Democritus, Dalton, or both? Atoms cannot be divided.
both
Steps of a nuclear reaction
1. An atom has an unstable nucleus 2. Radiation is emitted 3. The process of radioactive decay continues until the nucleus is stable 4. A stable non radioactive atom is formed
After years of studying (1.______________), Dalton was able to accurately determine the (2._______________) of the elements involved in the reactions. His conclusions resulted in the (3.____________), which helped to explain that (4.______________) in chemical reactions separate, (5.______________), or (6._____________), but are not created, (7._______________), or (8.________________).
1. Chemical reactions 2. Mass ratios 3. Atomic theory 4. Atoms 5. Combine 6. rearrange 7. Destroyed 8. Divided
Most of the area in the atom is made up of negatively charged (1.______________) traveling around the positively charged (2.______________).
1. Electrons 2. Nucleus
Dalton's atomic theory
1. Matter is composed of extremely small particles called atoms 2. Atoms are indivisible and destructible *they are divisible 3. Atoms of a given element are identical in size, mass, and chemical properties; atoms of a specific element are different of those from another element 4. Different atoms combine in simple whole-number ratios to form compounds 5. In a chemical reaction, atoms are separated combined, or rearranged
The mass of (1.__________) and (2.___________) are almost always equal to each other while the mass of the (3.______________) are really small.
1. Protons 2. Neutrons 3. Electrons
Each atom has a unique number of (1._____________). Since the overall charge of an atom is neutral the number of (2.____________) equals the number of (3.______________). *once you know the atomic number you can find the element
1. Protons 2. Protons 3. Electrons
The atoms is the (1.____________________________). When a group of atoms (2._____________) and act as a (3.________________), the result is known as a (4._______________).
1. Smallest part of an element 2. Bond 3. Unit 4. Molecule
Electron 1. Symbol: 2. Location: 3. Charge: 4. Mass:
1. Symbol: e- 2. Location: electron cloud surrounding nucleus 3. Charge: 1- or -1 4. Mass: 1/1840 amu
Neutron 1. Symbol: 2. Location: 3. Charge: 4. Mass:
1. Symbol: n, n°, n +/- 2. Location: in nucleus 3. Charge: 0 4. Mass: 1 amu
Proton 1. Symbol: 2. Location: 3. Charge: 4. Mass:
1. Symbol: p+ 2. Location: nucleus 3. Charge: +1 or 1+ 4. Mass: 1 amu
Radiation type: Alpha
1. Symbol: α 2. Mass (amu): 4 3. Charge: +2
Radiation type: Beta
1. Symbol: β 2. Mass (amu): 1/1840 3. Charge: 0
Radiation type: Gamma
1. Symbol: γ 2. Mass (amu): 0 3. Charge: 0
One atomic mass unit is ... ?
1/12 the mass of a carbon-12 atom.
atomic mass unit (amu)
1/12 the mass of a carbon-12 atom; the standard unit of measurement for the mass of atoms
Rutherfordium's atomic number is 104. How many p+ and e- does it have?
104 each
What is Neon-22 in symbolic notation?
22/10 Ne (Atomic mass/ atomic #) > Symbol
An isotope has atomic number 19 and mass number 39. How many protons, electrons, & neutrons does it have?
39-19=20 p&e= 19 n=20
The nucleus makes up about what percentage of the mass of an atom?
99.97%
nuclear reaction
A reaction in which the atom of 1 element changes into the atom of another element (transmutation)
radioactive decay
A spontaneous process in which unstable nuclei lose energy by emitting radiation
There (are/are not) instruments powerful enough to magnify atoms so that they can be seen
Are
Isotopes
Atoms with the same number of protons but different numbers of neutrons
Democritus, Dalton, or both? Different atoms combine in whole-number ratios to form compounds.
Dalton
Democritus, Dalton, or both? Different kinds of atoms come in different sizes and shapes.
Democritus
Democritus, Dalton, or both? Matter is made of empty space through which atoms move.
Democritus
Democritus, Dalton, or both? The properties of atoms vary based on shape, size, and movement.
Democritus
Both Democritus and Dalton (did/did not) suggest that matter is made up of atoms
Did
Dalton (did/did not) think that all atoms of a specific element have the same mass
Did
Dalton's atomic theory (did/did not) state that atoms of different elements combing in simple whole-number ratios to form compounds
Did
Dalton's atomic theory (did/did not) state that atoms separate, combine, or rearrange in chemical reactions
Did
Philosophers (did/did not) formulate explanations about the nature of matter based on their own experiments.
Did
Ancient philosophers (did/did not) regularly perform controlled experiments.
Did not
Dalton's atomic theory (did/did not) state that matter is mostly empty space
Did not
Democtritus (did/did not) propose that atoms are held together by chemical bonds, but no one believed him
Did not
Who determined the mass-to-charge ratio of an electron?
J.J. Thomson
Nucleus
Made of positive charged protons and neutral neutrons
To find the number of neutrons in an isotope:
Mass number - atomic number = # of n°
Electron
Negative charged fast moving particle, small mass, found in all forms of matter & moves through empty space
Neutron
Neutral, subatomic particle in an atom's nucleus that has a mass nearly equal to that of a proton
alpha particle
Particle with 2 protons and 2 neutrons emitted from a nucleus in with a 2+ charge emitted during radioactivity
Which plate do the beta particles bend toward?
Positive, they are negatively charged
Radiation
Rise in particles emitted by radioactive materials
Who calculated the mass of an electron?
Robert Millikan
Who proposed the nuclear atomic model?
Rutherford
Proton
Substance particle in an atom's nucleus that has a charge of +1 or 1+
Radioactivity
The process in which some substances spontaneously emit radiation
Atoms
The smallest unit of an element that maintains the properties of that element
Why do gamma rays not bend?
They have no charge
Dalton's atomic theory (was/was not) based on careful measurements & extensive research
Was
Dalton (was/was not) correct in thinking that atoms could not be divided into smaller particles
Was not
nuclear equation
a type of equation that shows the atomic number and mass number of the particles involved in radioactive decay
Democritus, Dalton, or both? All matter is made of tiny pieces.
both
Democritus, Dalton, or both? Atoms cannot be created.
both
specific
characterized by precise formulation or accurate restriction
isotope notation
element name- atomic mass
beta particle
fast moving electron with a -1 charge emitted by radioactive decay of substances
gamma rays
high energy radiation that has no charge and no mass and is not deflected by electronic or magnetic fields
nuclear notation
mass # (protons and neutrons)/ atomic # (protons) then followed by element symbol
cathode ray
radiation that originates from the cathode and travels to the anode of a cathode-ray tube
alpha radiation
radiation that was deflected toward the negatively charged plate *alpha particles are large particles
beta radiation
radiation that was deflected toward the positively charged plate
atomic number
the number of protons in an atom
atom
the smallest part of an element that retains all properties of that element
mass number
the sum of the number of neutrons and protons in the nucleus
atomic mass
the weighted average of the masses of the isotopes of an element
The mass of an electron is ... ?
• smaller than the mass of a proton • smaller than the mass of a neutron • a tiny fraction of the mass of an atom