Chapter 2 SmartBook Bio 181
An atom has 11 protons, 12 neutrons, and 10 electrons. This atom has an atomic number of ______, an atomic mass of ______, and an overall charge of ______.
*11; 23; +1* 11; 23; +1 11; 12; +1 23; 12; +1
The green sphere in the simple "Bohr model" of atoms shown here represents which of the following?
*An electron* An orbital A proton An energy level A neutron Reason: The atom on the left has one tan sphere and no purple spheres in the nucleus. Therefore, tan must represent protons and purple neutrons because all atoms must have at least one proton.
In the diagram, the 2 black circles (marked with two arrows) surrounding the large green sphere represent which of the following (choose all that apply)?
*Electron shells Electron energy levels* The nucleus Reason: the large green sphere in the center represents the nucleus
True or false: Electrons are found in the atom's nucleus
*False* True Reason: Protons and neutrons comprise the atom's nucleus; electrons are found in orbitals.
If an atom gains or loses electrons, it is known as which of the following?
*Ion* Isotope Anion Reason: This term describes an atom that has gained electrons but not an atom that has lost electrons. Cation Reason: This term describes an atom that has lost electrons but not an atom that has gained electrons.
In the simple "Bohr model" of atoms shown here, the tan spheres represent which of the following?
*Protons* Electrons Daltons Orbitals
Which of the following are subatomic particles?
*Protons* *Electrons* *Neutrons* Orbitals Reason: orbitals refer to the volume of space where electrons are most likely to be found Ions Reason: ions are atoms or molecules that have gained or lost electrons
Which subatomic particles are located in the nucleus of an atom (choose all that apply)?
*Protons* *Neutrons* Electrons Reason: Electrons are found in orbitals surrounding the nucleus. ions Reason: Ions are atoms that have lost or gained one or more electrons.
Which of the following (choose all that apply) correctly describe electrons within atoms?
*They occupy discrete energy levels.* They follow a specific path or orbit as they move around the nucleus. Reason: Electrons don't follow a path. They occupy a space around the nucleus (called an orbital) with a certain probability. They cannot move from one energy level to another. Reason: If an electron receives an input of energy, it can move to a more distant energy level. Similarly, an electron can move to an orbital that is closer to the nucleus and, in the process, release energy.
If two atoms have the same number of protons in their nucleus, you can conclude for sure that they
*are atoms of the same element* are the same isotope Reason: Just because two atoms have the same number of protons in their nucleus, does not mean they are the same isotope. They could have different numbers of neutrons, which would make them two different isotopes of the same element. have the same atomic mass Reason: Just because two atoms have the same number of protons in their nucleus, does not mean they have the same atomic mass. They could have different numbers of neutrons, which would make them have different atomic masses.
Atoms are composed of a central -------,which is surrounded by orbiting
*nucleus* *electrons*
Atoms of different chemical elements can be differentiated based on the number of-----
*protons in the nucleus* electrons in all shells electrons in the outermost shell Reason: Although the number of electrons matches the number of protons in uncharged atoms, the number of electrons varies in ions. The identify of the element is based on the number of protons. orbitals in the outermost shell neutrons in the nucleus Reason: Elements are identified based on the number of protons they contain. The number of neutrons is used to distinguish different isotopes of the same element from one another.
Match each subatomic particle with its electrical charge.
0 neutron +1 proton -1 electron
An electrically neutral atom has an atomic number of 11 and an atomic mass of 23. This atom has ________protons, _______neutrons, and _________ electrons.
11,12,11
No orbital can contain more than
2 electrons
This question refers to elements in the main groups of the periodic table. According to the octet rule, if an atom's first energy level is the outermost shell then it is stable with __________electrons and if an atom has any other energy level as its outermost shell then it is stable with _______electrons.
2,8
An electrically neutral atom has an atomic number of 6 and an atomic mass of 14. This atom has ___________protons, ______neutrons, and _____________electrons.
6,8,6
An atom has 8 protons, 9 neutrons, and 8 electrons. This atom has an atomic number of ______, an atomic mass of ______, and an overall charge of ______.
8; 17; 0
Identify the four most abundant elements in living organisms.
Carbon Nitrogen Oxygen Hydrogen
A sodium atom that has lost an electron and has an overall positive charge is an example of which of the following?
Cation
Valence electrons and their interactions determine the ________ properties of an element.
Chemical
For any given isotope, such as C-14, the rate of decay can be described as which of the following?
Constant
Atomic mass is measured in which of the following units?
Daltons (Da)
How does the decay rate of different radioactive isotopes compare?
Different radioactive isotopes decay at different rates.
The volume of space around the nucleus where an electron is most likely to be found is known as which of the following?
Electron orbital
In the diagram, the purple shapes represent which of the following?
Electron orbitals
Redox reactions involve a transfer of _________ from one atom to another.
Electrons
The number and configuration of ______ determines the chemical behavior of an atom.
Electrons
It takes work to keep electrons in their orbitals due to which of the following?
Electrons are attracted to the nucleus.
Anything that has mass and occupies space is defined as which of the following?
Energy Atomic Weight *Matter*
The letters K, L, M, and so on are used to designate which of the following?
Energy levels
In order for an electron to move to a more distal orbital which of the following must occur?
Energy must be added
The rate of decay for a radioactive isotope is usually expressed using which of the following?
Half-life
Within an atom, where are electrons found?
In orbitals that surround the nucleus
How are ions formed?
Ions are formed when atoms lose or gain one or more electrons.
Electrons are attracted to the positive charge of the nucleus, therefore, which of the following is true?
It takes work to keep them in their orbitals.
Electrons that are closer to the nucleus always have which of the following?
Less potential energy
During radioactive decay, an atom typically breaks up into elements with which of the following?
Lower atomic numbers
A dalton is a unit of which of the following?
Mass
Anything that has mass and occupies space is defined as
Matter
Atoms are composed of which of the following?
Molecules Ions Macromolecules *Subatomic particles*
Electrons that are farther from the nucleus always have which of the following?
More potential energy
Isotopes are atoms of the same element that differ in the number of which of the following?
Neutrons
Almost all the mass of an atom is located in which of the following?
Nucleus
Different isotopes of an element behave the same way chemically because they have the same number of which of the following?
Number of electrons
Atoms are composed of a central nucleus which is surrounded by which orbiting particles?
Protons *Electrons* Ions Neutrons
Among subatomic particles, each _______has a charge of +1, each ______has a charge of -1, and each ________has no charge.
Protons Electrons Neutrons
Which two particles are the primary determinants of an element's atomic mass?
Protons Neutrons
The atomic mass of an atom is equal to the sum of the masses of its
Protons and neutrons
Which subatomic particles determine the atomic mass of an atom?
Protons and neutrons
Different isotopes of an element behave the same way chemically not because they have the same number of ___________, but because they have the same number of ____________.
Protons or neutrons electrons
Which of the following defines isotopes that are unstable and tend to break apart into elements with lower atomic numbers while releasing a significant amount of energy?
Radioactive
__________isotopes are often used to label or "tag" specific molecules and then follow their progress either in a chemical reaction or in living cells and tissues.
Radioactive
isotopes, such as carbon-14, are unstable and tend to break apart into elements with lower atomic numbers while releasing a significant amount of energy.
Radioactive
When a larger atom breaks apart into smaller atoms, along with the release of a significant amount of energy, this is referred to as which of the following?
Radioactive decay
Chemical reactions that involve a transfer of electrons from one atom to another are called
Redox reactions
What shape do s orbitals assume?
Spherical
What is the main downside to using radioactive isotopes to label molecules within living cells?
Subatomic particles emitted by unstable isotopes may damage living cells.
In a neutral atom, the number of electrons is equal to which of the following?
The atomic number
Electrons with the same potential energy always occupy which of the following
The same energy level
What is the half-life of an isotope?
The time it takes for one-half of the radioactive isotope atoms in a sample to decay.
Why is an atom electrically neutral?
There are equal numbers of protons and electrons in the atom.
Choose all statements that describe atoms that have unfilled electron shells?
They can form bonds with other atoms They are chemically reactive. They can form chemical compounds.
Which of the following are some possible harmful effects of radioactive isotopes in cells?
They can lead to cell death in high doses. They can produce genetic mutations.
The different energy levels of electrons within atoms can be described as which of the following?
They can only take certain discrete values that correspond to quanta.
Why do elements in the same chemical group have the same bonding properties?
They have the same number of valence electrons
Carbon and silicon are both found in the same group of the periodic table. Carbon shares very similar bonding properties with silicon due to which of the following?
They have the same number of valence electrons.
Consider two electrons. One is located in the 2s orbital of an atom and the other in a 2p orbital of the same atom. Which of the following statements about those two electrons is true?
They have the same potential energy.
If two atoms belong to the same element, which of the following must be true?
They must have the same number of protons.
Electrons in outer, unfilled energy levels are known as ________________ electrons.
Valence
Electrons in the same energy level
always have the same potential energy
Atoms with a net negative charge are known as _______,whereas atoms with a net positive charge are known as
anions cations
Carbon-12, carbon-13, and carbon-14 are
different isotopes of the same element
What shape do p orbitals have?
dumbbell
If an atom gains or loses a(n) ----------, it acquires a net electrical charge and becomes an ion.
electron
Subatomic particles called -----can be found at various distances from the nucleus (please only write the name of the particle without specifying its charge or other properties).
electrons
A substance that cannot be broken down into simpler substances by ordinary chemical means is called a(n)
element
When electrons move closer to the nucleus,
energy is released.
The letters K, L, M, and so on are used to designate different
energy levels in an atom
--------atoms always have one proton.
hydrogen
By determining the ratio of the different ___________of carbon and other elements in a sample, scientists are able to accurately determine the age of the sample.
isotopes
Carbon-12, carbon-13, and carbon-14 are examples of different
isotopes
Scientists often need to follow specific molecules and their progress either in a chemical reaction or in living cells and tissues. In such studies, radioactive isotopes can be used to
label the molecules.
If two electrons occupy different orbitals, they
may or may not have the same potential energies.
Isotopes differ in the number of________ they contain.
neutrons
Almost all the mass of an atom is located in the
nucleus
Atoms are composed of a central ------which is surrounded by orbiting --------
nucleus electrons or electron cloud
Electron __________represent probability distributions for electrons, that is, regions surrounding the nucleus where there is the highest probability of finding electrons.
orbitals
An atom participating in a chemical reaction loses one or more electrons. The process of losing an electron in a reaction is called
oxidation
--------atoms usually have no neutrons.
protium
Atomic number refers to the number of ----------in an atom. Atomic number refers to the number of which of the following?
protons
Atoms of the same element always have the same number of protons , --------in the nucleus, and this number is unique for that element.
protons
The three main types of subatomic particles are-------- --------- ----------
protons neutrons electrons
Within an atom, ______ and ______ have nearly equal masses, while ______ have a much smaller mass.
protons; neutrons; electrons
An atom participating in a chemical reaction gains one or more electrons. The process of gaining electrons in a reaction is called
reduction
All atoms are composed of several types of------- protons , Incorrect Unavailable particles. A proton is an example of such a particle.
subatomic
By determining the ratio of the different isotopes of carbon in a sample, scientists are able to accurately determine which information about the sample?
Age
What do we call a substance that cannot be broken down into simpler substances by ordinary chemical means?
An element
A chlorine atom that has gained an electron and has an overall negative charge is an example of which of the following?
Anion
The number and configuration of electrons determines an element's
chemical properties
