Science Chapter 4
If an atom of an element has a mass number of 31 and 16 neutrons in its nucleus, what is the atomic number of the element?
31 - 16 = 15
A certain atom has 26 protons, 26 electrons, and 30 neutrons. Its mass number is
56
If an atom of germanium has a mass number of 70 and an atomic number of 32, how many neutrons are in its nucleus?
70 - 32 = 38
A sample of calcium contains calcium-40, calcium-44, calcium-42, calcium-48, calcium-43, and calcium-46 atoms. Explain why these atoms can have different mass numbers, but they must have the same atomic number.
All the atoms of an element have the same number of protons.
According to ______ all matter was made up of four elements- earth, air, fire, and water
Aristotle
The Greek philosopher Democritus coined what word for a tiny piece of matter that cannot be divided?
Atom
The number of protons in one atom of an element is that element's
Atomic Number
To find the number of neutrons in an atom, you would subtract
Atomic number from mass number
Which of the following is NOT part of John Dalton's atomic theory?
Atoms contain subatomic particles
J.J. Thomson's experiment provided evidence that an atom
Contains negatively charged particles.
What specific word comes from a Greek word meaning "uncut"? Which Greek philosopher first used the word to describe matter?
Democritus - Proposed the word atomos.
A particle that moves around the nucleus is an
Electron
The _____ in an atom has a negative charge
Electron
Which subatomic particle has a negative charge?
Electron
Each inner energy level of an atom has a maximum number of ______ it can hold.
Electrons
Compare the masses of neutrons, protons, and electrons.
Electrons have an extremely small mass, compared to either protons and neutrons.
Who provided evidence for the existence of a nucleus in an atom?
Ernest Rutherford
The maximum number of electrons in the second energy level of an atom is 4.
False: Eight
The region around the nucleus occupied by the electrons is called the negative zone.
False: Electron Cloud
The mass of an (electron) is about equal to the mass of a proton.
False: Neutron
The central core of an atom is called the hub.
False: Nucleus
Two isotopes of carbon are carbon-12 and carbon-14. These isotopes differ from one another by two protons.
False: neutrons
Atoms of the same element with different numbers of neutrons are called
Isotopes
In Niels Bohr's model of the atom, electrons move
Like planets orbiting the sun.
Protons and _______ are found in the nucleus of an atom
Neutrons
The center of the atom where protons and neutrons are located is the
Nucleus
If element Q has 11 protons, its atomic ______ is 11.
Number
Which statement about subatomic particles is true?
Protons, neutrons, and electrons all have about the same mass.
Particles of matter that make up protons and neutrons are
Quarks
Which statement is true about oxygen-17 and oxygen-18?
They are isotopes of oxygen
According to present atomic theory, the location of an (electron) in an atom cannot be pinpointed exactly.
True
So far, scientists have conformed the existence of (six) different quarks.
True
The sum of the number of protons and neutrons in an atom is the mass number.
True
Which of the following most accurately represents John Dalton's model of the atom?
a tiny, solid sphere with a predictable mass for a given element
In Bohr's model of the atom, ______ move in fixed orbits around the nucleus
electrons
John Dalton concluded that all the atoms of a single _______ have the same mass
element
The subatomic particle that J.J. Thomson discovered has a _____ charge
negative
The nuclei of isotopes contain different numbers of
neutrons
The region in which an electron is most likely to be found is called an
orbital
Horizontal rows of the periodic table is called
periods