Chemistry Unit 2
Scandium (Sc) has _____ protons in its nucleus.
21
The atomic number for nickel (Ni) is ____________ .
28
Ion
A charged atom
Law of difinite proportions
A given chemical compound always contains its component elements in fixed ratio and does not depend on its source and method of preparation
Anion
A negatively charged ion
Cation
A positively charged ion
Isotope
Atoms of the same element that have different numbers of neutrons
Rutherford's experiment showed that most of the atom was ______ _______ .
EMPTY SPACE
True or False: 42/20 Ca The subscript always stands for the number of neutrons in the atom.
F (atomic number = # of protons)
True or False: All atoms of a given element are identical.
F (isotopes differ by mass)
True or False: Rutherford's experiments showed the location of the electron.
F (showed location of proton)
True or False: If 125 grams of reactants are used in a reaction, only 50 grams of product are expected.
False (Law of Conservation of Mass says masses should be the same)
True or False: Atoms of one element may be the same as atoms of a different element.
False (atoms of different elements are different)
True or False: The cathode rays were deflected towards a negatively charged metal plate.
False (away from)
True or False: The number of positively charged protons must equal the number of negatively charged electrons.
False (can have ions (charged atoms) where they would be different)
True or False: Electrons contribute a large amount to the atomic mass of an element.
False (electrons have little mass)
True or False: Most elements do not have isotopes.
False (most elements naturally exist as mixtures of isotopes)
True or False: None of the particles in Rutherford's experiment bounced back toward the source.
False (some did which led to his conclusions about the nucleus)
Law of Conservation of Mass
Matter is not created nor destroyed in any chemical or physical change
True or False: All atoms of the same element must have the same atomic number.
True
True or False: Atoms combine in small whole-number ratios to form compounds.
True
True or False: Atoms of different elements can combine in fractional ratios to form compounds.
True
True or False: Dalton assumed that atoms could not be broken down further.
True
True or False: In Rutherford's experiment, most of the particles passed through the gold foil.
True
True or False: Isotopes of a given element have the same number of electrons.
True
True or False: Rutherford felt that all the atom's positive charge was in the nucleus.
True
True or False: Some elements can combine to form more than one compound.
True
True or False: The neutron has approximately the same mass as the proton.
True
True or False: The number of neutrons will not always equal the number of electrons in the atom.
True
True or False: The presence of isotopes does not affect chemical reactivity for an element.
True
Rutherford's experiment used _________ to bombard the foil. a. alpha particles b. beta particles c. gamma particles d. delta particles
a. alpha particles
By the 1700s chemists had accepted the idea of a. an element b. atomic structure c. existence of electrons d. element sub-particles
a. an element
Millikan's oil drop experiment determined the mass of the a. electron b. neutron c. proton d. atomic nucleus
a. electron
Masses of individual atoms can be determined by a. mass spectrometer b. atomic balance c. mass fluorometer d. fluorescence radiation
a. mass spectrometer
The atomic number for an element indicates the number of a. protons b. neutrons c. electrons d. muons
a. protons
Chemical reactions do not involve the _________ of atoms. a. transmutation b. separation c. combination d. rearrangement
a. transmutation
The law of definite proportions means that a. all compounds have similar compositions b. all samples of the same compound have the same composition c. sample of a compound from different sources can have different compositions d. a compound might have different amounts of atoms
b. all samples of the same compound have the same composition
John Dalton proposed that all matter was composed of a. elements b. atoms c. compounds d. particles
b. atoms
Isotopes of an element differ only by a. number of electrons b. number of neutrons c. number of protons d. number of neurons + electrons
b. number of neutrons
One of the following is not a main subatomic particle a. proton b. positron c. electron d. neutron
b. positron
The nucleus of the atom is composed of a. protons and electrons b. protons and neutrons c. neutrons and electrons d. protons and positrons
b. protons and neutrons
All atoms of a specific element must have all but one of the following a. same size b. same mass c. same color d. same reactivity
b. same mass
J.J. Thomson carried out experiments with a. an X-ray tube b. a test tube c. a cathode ray tube d. a fluorescent tube
c. a cathode ray tube
An atomic mass unit is defined in relation to the ______ atom. a. hydrogen b. fluorine c. carbon d. nitrogen
c. carbon
One of the following is not true about Democritus a. he was a Greek philosopher b. he suggested that atoms were the basic units of matter c. his ideas were quickly accepted d. his approach was philosophical, not experimental
c. his ideas were quickly accepted
Complete atoms are electrically a. positive b. negative c. neutral d. complex
c. neutral
Naturally occurring carbon has _____ isotopes. a. one b. four c. three d. two
c. three
The mass number for an element is the a. total number of subatomic particles b. total number of protons and electrons c. total number of protons and neutrons b. total number of neutrons and electrons
c. total number of protons and neutrons
Carbon and oxygen can combine to form a. only one compound b. many different compounds c. two different compounds d. three different compounds
c. two different compounds
Only one of the following is an appropriate way to indicate an isotope of iodine (I) with an atomic mass of 131 a. I b. 131I c. 131-I d. I-131
d. I-131
Elements can combine to form a. other elements b. gold c. reactants d. compounds
d. compounds
Rutherford performed the _________ foil experiment to study atomic structure. a. alpha b. beta c. silver d. gold
d. gold
Dalton's atomic theory was based on all of the following except a. law of conservation of mass b. law of definite proportions c. law of multiple proportions d. law of conservation of energy
d. law of conservation of energy
The number of neutrons in an atom equals a. mass number - number of electrons b. number of protons - mass number c. number of protons d. mass number - number of protons
d. mass number - number of protons
Cathode rays were shown to be streams of __________ particles. a. positively charge particles b. electrically neutral particles c. a mixed of charged particles d. negatively charged particles
d. negatively charged particles
An atom can be classified as a particular element based on a. atomic mass b. number of neutrons c. molar mass d. number of protons
d. number of protons
J.J. Thomson developed the __________ model of the atom a. apple pie b. rice pudding c. cherry pie d. plum pudding
d. plum pudding
Chemical behavior is determined by the number of a. protons + neutrons b. protons + electrons c. neutrons + electrons d. protons alone
d. protons alone
Law of Multiple Proportions
if two or more different compounds are composed of the same two elements, then the ratio of the masses of the second element combined with a certain mass of the first element is always a ratio of small whole numbers
"Atomos" is a Greek word that means _____________ .
indivisible
Atomic Mass
the mass of an atom of a chemical element expressed in atomic mass units. It is approximately equivalent to the number of protons and neutrons in the atom (the mass number) or to the average number allowing for the relative abundances of different isotopes.
Atomic Number
the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place on the periodic table
Mass Number
the total number of protons and neutrons in the nucleus
