Module 4 - Atoms V5 Flashcards
The law of constant composition states that all samples of a pure compound will always have the same elements in the same proportion.
true
An element consists of more than one type of atom.
false
Who discovered the atom?
Leucippus and Democritus
Which scientist is credited with discovering the electron?
Thomson
Electrons are positively charged.
false
Electrons are smaller than protons.
true
The mass number is always equal to the charge.
false
The atomic number of an atom is equal to…
the number of protons
The mass number is the number of electrons and protons in an atom.
false
Isotopes are not naturally present in nature.
false
The average atomic mass of an element does not account for naturally occurring isotopes.
false
What subatomic particle is not considered when calculating atomic mass?
electrons
The horizontal rows of the periodic table are called…
periods
The periodic table has 7 periods.
true
A nonmetal is a shiny, malleable element that is a good conductor of heat and electricity.
false
Who is often considered to be the father of atomic theory?
Dalton
Which is not a postulate of Dalton’s atomic theory?
An element consists of multiple types of atoms.
Thomson conducted the oil drop experiment, resulting in the calculation of electrical charge.
false
Based on the results of the gold foil experiment, Rutherford is known for his discovery of the…
proton
Millikan conducted the oil drop experiment, which resulted in the discovery of how the _____ of a(n) _____ is calculated.
mass; electron
_________ came up with the plum pudding model of the atom following his discovery of the electron.
Thomson
Which is not a subatomic particle?
isotope
The ______ is the center of an atom.
nucleus
The nucleus is negatively charged.
false
In the chemical symbol for hydrogen, what does the +1 refer to?
charge
How are isotopes different from their original element?
Isotopes have a different number of neutrons.
Which series is correct for fluorine-19?
9 protons, 9 electrons, 10 neutrons, atomic number 9, mass number 19
What is the average atomic mass of beryllium?
9.0122amu
What is the average atomic mass of nitrogen?
14.006amu
Suppose that naturally occurring rubidium with an average atomic mass of 85.468 amu has 2 isotopes, Rubidium-85 and Rubidium-87 with atomic masses 84.911 amu and 86.909 amu, respectively. What is the percent abundance of Rubidium-85?
72%
The periodic table is arranged in order by increasing…
atomic number
Which is not displayed for each element in the periodic table?
isotope numbers
The atomic number is equal to the number of electrons in an element.
false
The rows in the periodic table are called…
periods
Which is not considered a main group in the periodic table?
lanthanides
Who is often considered to be the father of atomic theory?
Dalton
Which postulate of Dalton’s atomic theory was proven wrong?
all matter is composed of atoms which are indivisible
Which is not a postulate of Dalton’s atomic theory?
atoms can be broken into smaller pieces
When was the atom discovered?
the 5th century BCE
Why were two postulates of Dalton’s atomic theory proven wrong?
it was discovered that elements can have isotopes
Which subatomic particle is positively charged?
proton
Which experiment contributed to the discovery that atoms are mostly empty space?
gold-foil
Which scientist conducted the oil drop experiment?
Millikan
Which experiment calculated the charge of a single electron?
oil drop
Which proposed model of the atom included a small positively charged nucleus?
Rutherford’s model
Calculate the mass number of an atom with 10 protons, 9 neutrons, and 10 electrons.
19
Which subatomic particle is negative?
electron
Which subatomic particle is the least massive?
electron
How many protons are in the following chemical symbol: lithium?
3
What is the atomic number of the following chemical symbol: Carbon?
6
The atomic number is…
the number of protons in an atom.
__________ is the total number of protons and neutrons in an atom.
mass number
Which of the following is not necessary information for calculating percentage abundance?
natural abundance
An isotope contains different numbers of…
neutrons
Which element has only one isotope?
fluorine
Carbon is a…
nonmetal
The periodic table was invented by…
Mendeleev
Where are the radioactive elements located on the periodic table?
actinides
Which is not a region of the periodic table?
periodic law
How is the modern periodic table organized?
atomic number
