Democritus was known for

creating the term atom, meaning indivisible

The average atomic mass of an element

may not equal the mass of any of its isotopes

Ernest Rutherford discovered

the nucleus and it has all the mass of an atom

The law of conservation of mass states:

Mass of the products equals the mass of the reactants

Werner Heiseinberg stated:

it was impossible to show exact position& speed of electrons

According Dalton's atomic theory, atoms

of each element are identical in size, mass&other properties

common substances always broke down into the same elements

that electron orbited the nucleus at fixed energies&distance

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Chapter 3

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Mole conversions, Isotopes, atomic theory and structure of an atom

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Questions 18

Answers

1
Democritus was known for
creating the term atom, meaning indivisible
discovered the electron
discovered the nucleus
discovered the proton
2
All atoms of the same element have the same
number of neutrons
atomic mass
mass number
number of protons
3
What type of charge does a proton have and where is it located?
negative; nucleus
positive; nucleus
negative; outside the nucleus
positive; outside the nucleus
4
How many moles are in 56.2 g of cadmium?
338.32 mol
0.25 mol
0.50 g
0.50 mol
5
The average atomic mass of an element
cannot be calculated
always adds up to 100
is the mass of the most abundant isotope
may not equal the mass of any of its isotopes
6
How many neutrons are in the following isotope?
1 neutron
2 neutrons
4 neutrons
0 neutrons
7
Ernest Rutherford discovered
the nucleus and it has all the mass of an atom
the proton and it is positive
the electron and it is negative
substance broke down into th same element in same proportion
8
The law of conservation of mass states:
Energy cannot be created nor destroyed
Mass of the products equals the mass of the reactants
Energy of the products will equal the energy of
Mass of the products will not equal the mass of the products
9
J.J. Thomson discovered:
the atom
the electron
the nucleus
the proton
10
Werner Heiseinberg stated:
it was impossible to show exact position& speed of electrons
matter was made up of earth, air, wind and fire
common substances broke down into the same elements
most of the mass of an atom is in the nucleus
11
The atomic mass of elements has a standard element. It is
Carbon-12
Hydrogen-3
Oxygen-16
Carbon-14
12
How many atoms are in 1.55 mol of phosphorus?
48.0 g
48.0 atoms
1.55 x 1023 atoms
9.33 x 1023 atoms
13
According Dalton's atomic theory, atoms
are destroyed in chemical reactions
of each element are identical in size, mass&other properties
of different elements cannot combine
can be divided
14
John Dalton stated
that a proton is positive
that an electron is negative
that a nucleus has all of the mass
common substances always broke down into the same elements
15
The mass number of an atom can be calculated by:
adding protons and electrons
subtract protons by electrons
subtract electrons by neutrons
adding protons and neutrons
16
Niels Bohr believed
the nucleus has all the mass in an atom
that electron orbited the nucleus at fixed energies&distance
that matter was made up of earth, air, wind and fire
it was possible to show exact position and speed of electron
17
How many neutrons are in Lithium-8?
5 neutrons
3 neutrons
5 neutrons
8 neutrons
18
What is Avogadro's number?
6.02 x 1023
896
1023
6.02

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