Chemistry Chapter 4
Circle the letter next to the number of units of positive charge that remain if a hydrogen atom loses an electron
1
Circle the letter of each sentence that is true about Dalton's atomic theory 1. All elements are composed of tiny, indivisible particles called atoms 2. An element is composed of several types of atoms 3. Atoms of different elements can physically mix together, or can chemically combine in simple whole-number ratios to form compounds. 4. Chemical reactions occur when atoms are separated, joined, or rearranged; however atoms, of one element are never changed into atoms of another element by a chemical reaction
1,3,4
Atomic Mass Unit
1/12 the mass of a carbon-12 atom
About how many atoms of copper when placed side by side would form a line 1 cm long
100,000,000
How do atoms of neon-20 and neon-22 differ?
2 nuetrons
What is the mass number of a helium atom that has two protons and two neutrons
4
An atom of an element with atomic number 48 and mass number 120 contains 1. 48 protons, 48 electrons, and 72 neutrons 2. 72 protons, 48 electrons, and 48 neutrons 3. 120 protons, 48 electrons, and 72 neutrons 4. 72 protons, 72 electrons, and 48 neutrons.
48 protons, 48 electrons, and 72 neutrons
How many neutrons does a beryllium atom with four protons and a mass number of nine have
5
Period
A horizontal row of elements in the periodic table
Relative atomic masses are measured to
Amus
How is the atomic theory that is accepted today different from Dalton's atomic theory?
An atom can be further subdivided into protons, neutrons, and electrons.
Hydrogen's atomic number, Number of protons, and Number of electrons
Atomic Number: 1 Number of Protons: 1 Number of Electrons: 1
Helium's atomic number, Number of protons, and Number of electrons
Atomic Number: 2 Number of Protons: 2 Number of Electrons: 2
Lithium's atomic number, Number of protons, and Number of electrons
Atomic Number: 3 Number of Protons: 3 Number of Electrons: 3
Boron's atomic number, Number of protons, and Number of electrons
Atomic Number: 5 Number of Protons: 5 Number of Electrons: 5
Carbon's atomic number, Number of protons, and Number of electrons
Atomic Number: 6 Number of Protons: 6 Number of Electrons: 6
Oxygen's atomic number, Number of protons, and Number of electrons
Atomic Number: 8 Number of Protons: 8 Number of Electrons: 8
Dalton's theorized that all atoms of are indivisible and that all atoms of an element are identical. Scientists know that 1. Dalton's theories are completely correct 2. Atoms of an element can have different numbers of protons 3. Atoms are divisible 4. All atoms of an element are not identical but they all have the same mass
Atoms are all divisible
Which of the following was not part of Dalton's atomic theory? 1. All elements are composed of atoms. 2. Atoms of the same element are alike. 3. Atoms are always in motion. 4. Atoms that combine do so in simple whole-number ratios.
Atoms are always in motion
Which of these statements is false? 1. Atoms of the same elements can have different masses 2. The nucleus of an atom has a positive charge 3. Atoms of isotopes of an element have a different number of protons. 4. Atoms are mostly empty space
Atoms of isotopes of an element have different numbers of protons
Explain how the atoms of one element differ from those of another element.
Atoms of one element will have a different mass number, and they will have a different number of protons, neutrons, and electrons compared to a different element.
Explain how the atoms of one isotope differ from those of other isotopes of the same element.
Atoms of one isotope has a different number of neutrons than those of other isotopes of the same element.
Isotopes
Atoms with the same number of protons but different numbers of neutrons
Circle the letter of each sentence that is true about atoms, matter, and electric charge. a. All atoms have an electric charge. b. Electric charges are carried by particles of matter. c. Electric charges always exist in whole-number multiples of a single basic unit. d. When a given number of positively charged particles combines with an equal number of negatively charged particles, an electrically neutral particle is formed.
B,C,D
If E is the symbol for an element, which two of the following symbols represent isotopes of the same element 1. 24/12 E 2. 24/13 E 3. 25/11 E 4. 25/12 E A. 1 and 2 B.3 and 4 C. 1 and 4 D. 2 and 3
C. 1 and 4
What isotope of carbon has been chosen as the reference isotope for atomic mass units? What is the defined atomic mass in amu of this isotope?
Carbon-12 ; 1/12 the mass of carbon=12
Thomas observed that the production of cathode rays did not depend on the gas in the tube or the type of metal used for the electrodes. What conclusion did he draw from these observations?
Cathode rays have identical properties regardless the element used to produce them.
Which of these statements is false? 1. Electrons have a negative charge. 2. Electrons have a mass of 1 amu 3. The nucleus of an atom is positively charged 4. The neutron is found in the nucleus of an atom
Electrons have a mass of 1 amu
List two reasons why the ideas of Democritus were not useful in a scientific sense
His ideas did not explain chemical behavior, and his ideas were not based on the scientific method
protium (hydrogen)
Hydrogen 1
deuterium
Hydrogen-2
tritium
Hydrogen-3
How do isotopes hydrogen-2 and hydrogen-3 differ 1. Hydrogen-3 has one more electron than hydrogen-2 2. Hydrogen-3 has two neutrons 3. Hydrogen-2 has three protons 4. Hydrogen-2 has no protons
Hydrogen-3 has two neutrons
The modern process of discovery about atoms began with the theories of an English school teacher named
John Dalton
What two properties of an electron did Robert Millikan determine from his experiments?
Mass of an electron is 1/1840 of the mass of a hydrogen atom and electrons have one unit of a negative charge
The nucleus of an atom is 1. Negatively charged and has a low density 2. Negatively charged and has a high density 3. Positively charged and has a low density. 4. Positively charged and has a high density
Positively charged and has a high density
Proton
Positively charged subatomic particle
Explain why in 1911 Rutherford and his coworkers were surprised when they shot a narrow beam of alpha particles through a thin sheet of gold foil.
Some of the particles were deflected and bounced back toward source. Atom was mostly empty space with a dense, positive center.
The number of neutrons in the nucleus of an atom can be calculated by 1. Adding together the numbers of electrons and protons 2. Subtracting the number of protons from the number of electrons 3. Subtracting the number of protons from the mass number 4. Adding the mass number to the number of protons
Subtracting the number of protons from the mass number
What is an electrons symbol, relative electric charge, relative mass ( mass of proton ), Actual mass
Symbol: e- Relative electric charge: 1- Relative mass: 1/1840 Actual Mass (g): 9.11 X 10 to the negative twenty-eighth power
What is a neutrons symbol, relative electric charge, relative mass ( mass of proton ), Actual mass
Symbol: n0 Relative electric charge: 0 Relative mass: 1 Actual Mass (g): 1.67 X 10 to the negative twenty-fourth power
What is a protons symbol, relative electric charge, relative mass ( mass of proton ), Actual mass
Symbol: p+ Relative electric charge: 1+ Relative mass: 1 Actual Mass (g): 1.67 X 10 to the negative twenty-fourth power
Why is the atomic mass unit (amu), rather than the gram, usually used to express atomic mass?
The mass of 1 atom is extremely small
Electron
a negatively charged subatomic particles
The positively charged particle that remains when a hydrogen atom loses an electron is called
a proton
In the periodic table, the elements are organized into groups based on
a set of repeating properties
Circle the letter of the correct answer. When chlorine occurs in nature, there are three atoms of chlorine-35 for every one atom of chlorine-37. Which atomic mass number is closer to the average atomic mass of chlorine A. 35 amu B. 37 amu
a. 35 amu
Circle the letter of each sentence that is true about the nuclear theory of atoms suggested by Rutherford's experimental results. a. An atom is mostly empty space. b. All the positive charge of an atom is in a small central region called the nucleus c. The nucleus is composed of protons d. The nucleus is large compared with the atom as a whole e. Nearly all the mass of an atom is in its nucleus
a. An atom is mostly empty space. b. All the positive charge of an atom is in a small central region called the nucleus e. Nearly all the mass of an atom is in its nucleus
Circle the letter of each statement that is true about the average atomic mass of an element and the relative abundance of its isotopes a. In nature, most elements occur as a mixture of two or more isotopes. b. Isotopes of an element do not have a specific natural percent abundance. c. The average atomic mass of an element is usually closest to that of the isotope with the highest natural abundance d. Because hydrogen has three isotopes with the atomic mass of about 1 amu, 2 amu, and 3 amu, respectively, the average atomic mass of natural hydrogen is 2 amu
a. In nature, most elements occur as a mixture of two or more isotopes. b. Isotopes of an element do not have a specific natural percent abundance. c. The average atomic mass of an element is usually closest to that of the isotope with the highest natural abundance
Suppose you can grin a sample of the element copper into smaller and smaller particles. The smallest particle that could no longer be divided, yet still has the chemical properties of copper is
an atom
an electrode with a positive charge
anode
In shorthand notation the number on the bottom is the
atomic number
Democritus, who lived in Greece during the fourth century B.C., suggested that matter is made up of tiny particles that cannot be divided. He called these particles
atoms
an electrode with a negative charge
cathode
a glowing beam traveling between charged electrodes
cathode ray
In shorthand notation the letters are the
chemical symbols
A negatively charged particle
electron
What subatomic particles carry a negative charge.
electrons
Is the following sentence true or false? The atomic mass of an element is always a whole number of atomic mass units
false
Neon-20 and Neon-22 are called isotopes
isotopes
In shorthand notation the number on top is the
mass number
The number 80 in the name bromine-80 represents 1. the atomic number 2. the mass number 3. the sum of protons and electrons 4. none of the above
mass number
The sum of protons and neutrons in an atom equals the 1. atomic number 2. number of electrons 3. atomic mass 4. mass number
mass number
The total number of protons and neutrons in an atom is its
mass number
What charge does a neutron carry?
neutral or no charge
All atoms of the same element have the same 1. number of protons 2. number of neutrons 3. mass number 4. mass
number of protons
What are the horizontal rows on the periodic table called?
period
Circle the letter of the term that correctly completes the sentence. Elements are different because their atoms contain different numbers of
protons
Nuetron
subatomic particle with no charge
Atomic Number
the number of protons in the nucleus of an atom
Atom
the smallest particle of an element that retains its identity in a chemical reaction
Mass Number
the total number of protons and neutrons in the nucleus of an atom
Atomic Mass
the weighted average mass of atoms in a naturally occurring sample of an element
Is the following sentence true or false? An alpha particle has a double positive charge because it is a helium atom that has lost two electrons
true
Is the following sentence true or false? Isotopes are chemically alike because they have identical numbers of protons and electrons
true
