unit 2: atomic theory and structure
Which statement is consistent with the results of Rutherford's gold foil experiment?
Atoms are mostly empty space
use the data from the four isotopes below to calculate the average atomic mass of element X. show your work. isotope name isotopic mass relative abundance (%) X-50 49.946 amu 4.35% X-52 51.941 amu 83.79% X-53 52.941 amu 9.50% X-54 53.939 amu 2.36%
51.996 chromium Cr
the element silver has two naturally occurring isotopes: silver-107 has an isotopes mass of 106.905 amu and a relative abundance of 51.84% silver-109 has an isotopes mass of 108.905 amu and a relative abundance of 48.16% calculate the average atomic mass of the element silver
108.8682
Element x has an atomic number of 35 and a mass number of 75 How many of each subatomic particle are in a neutral atom of the element?
35 protons, 40 neutrons, and 35 electrons
lithium has two naturally occurring isotopes. lithium-6 has an atomic mass of 6.015 amu and lithium-7 has an atomic mass of 7.016 amu the average atomic mass of lithium is 6.941 amu what is the percentage of naturally occurring lithium-7?
92.51%
neutron
A neutral, subatomic particle in an atom's nucleus that has a mass nearly equal to that of a proton
proton
A subatomic particle that has a positive charge and that is found in the nucleus of an atom
originally part of Dalton's atomic theory, but had to be revised later based o new experimental evidence
A) Atoms are tiny indivisible particles B) atoms of the same element are identical D) compounds are made by combining atoms
Based on Rutherford's discovery of the nucleus, which model of the atom is thought to be true?
Electrons are located around the nucleus and occupy most of the volume
Which of the following statements about atoms and subatomic particles is FALSE?
Electrons are negatively charged and have a mass of 1.
what occurred that gave evidence of electrons in all atoms (Cathode ray tube experiment)
He concluded negatively charged particles called electrons
Which of the following statements about atoms is FALSE?
Isotopes of an element have different numbers of protons
In which of the following is the number of neutrons correctly represented?
Mg has 12 neutrons
nitrogen has two naturally occurring isotopes, N-14 and N-15. The atomic mass of nitrogen is 14.01 amu. amu. Which isotopes is more abundant in nature? how can you tell?
N-14 the average atomic mass is closer to it
FALSE about subatomic particles
Neutrons have no charge and have no mass
compare and contrast Thomson's plum pudding atomic model with Rutherford's nuclear atomic model.(be sure to state how they're alike AND how they're different)
Thomson said the electrons are evenly tributed but they're not like that in Rutherford's model. They both talked about the positive charge but thomson referred to the whole atom and thomson reffered only to the nucleus as being positively charged
The fictitious element Z has two naturally occurring isotopes, Z-310 and Z-33 The average atomic mass of Z is found to be 311.02 amu. Which of the isotopes of the fictitious element Z is more abundant? Z-310 or Z-313 or equal abundant (circle one) How could you tell?
Z-310 because 311 is closer to 310 than it is to 312
a certain element has tree naturally occurring isotopes. what other information would you need in order to calculate he element's average atomic mass?
abundant percentage
all atoms of the same element have the same
atomic number
Write two statements from Dalton's atomic theory now considered to be invalid based on evidence.
atoms of the same element are always identical; atoms combine to form compounds
How does modern atomic theory differ from these statements
atoms of the same element are sometimes identical; atoms need a chemical reaction to form compounds
isotope
atoms of the same element with different number of neutrons
Which subatomic particle was discovered by researchers working with a cathode ray tube?
electrons
Which subatomic particles have charges (and what is their charge)?
electrons are negatively charged;protons are positively charged
what are atoms of the same element with different numbers of neutrons?
isotopes
use isotopes to explain why the atomic masses given on the periodic table are decimal numbers (not whole numbers)
it is the average atomic mass of all the isotopes with their abundance being a big factor
electron
negatively charged charged, fast-moving particle with an extremely small mass that is found in all forms of matter and moves through the empty space surrounding an atom's nucleus
What caused the deflection of the alpha particles in Ruherford's gold foil experiment?
nucleus
which subatomic particles account for most of an atom's mass?
nucleus and protons
all atoms of the same element have the same
number of protons
atomic number
number of protons in an atom
which subatomic particle identifies an atom as a particular element?
proton
how are isotopes of the same element alike? how are they different?
protons, atomic number neutrons, atomic mass
All atoms are neutral because the number of ---- always equals the number of---- in every atom
protons, electrons
Nucleus
the extremely small, positively charged, dense center of an atom that contains positively charged protons and neutral neutrons
mass number
the number after an element's name, representing the sum of its protons and neutrons
write one more about atoms that Rutherford made from this experiment.
the positive charge and mass of an atom is in the nucleus
what observation in this experiment by led to the theory that atoms are mostly empty space, and that almost aa of the mass of the atom is contained in a tiny, dense nucleus?
the rays went through the gold paper but every 1 in 1,000 bounced off of something
Atom
the smallest particle of an element that retains all the properties of that element
explain why isotopes of the same element are not considered different element.
they have the same amount of protons and electrons therefore having the same properties
atomic mass
weighted average of the isotopes of that element