Mastering Biology Chapter 2 Flashcards
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Questions and Answers

Atoms with the same number of protons but with different electrical charges _____.

are different ions

In salt, what is the nature of the bond between sodium and chlorine?

ionic

What is the result of the animated process?

a positively charged sodium ion and a negatively charged chlorine ion

An ionic bond involves _____.

<p>an attraction between ions of opposite charge</p> Signup and view all the answers

The brackets are indicating a(n) _____ bond.

<p>hydrogen</p> Signup and view all the answers

What name is given to the bond between water molecules?

<p>hydrogen</p> Signup and view all the answers

A carbon atom and a hydrogen atom form what type of bond in a molecule?

<p>nonpolar covalent bond</p> Signup and view all the answers

An ionic bond is formed when _____.

<p>one atom transfers an electron to another atom</p> Signup and view all the answers

Hydrogen bonding is most often seen _____.

<p>when hydrogen is covalently bonded to an electronegative atom</p> Signup and view all the answers

A cation with two units of charge has 10 neutrons and 8 protons. The ion also has...?

<p>6 electrons</p> Signup and view all the answers

Which statement is true of the molecule shown here?

<p>It's both a cation and an anion</p> Signup and view all the answers

The atoms shown here will become ions if they meet because...?

<p>atoms tend to avoid having a partly filled valence shell</p> Signup and view all the answers

True or false: Ions may form by transferring an atomic nucleus (with or without electrons) to another molecule.

<p>True</p> Signup and view all the answers

When chemists and biologists want to show how atoms are bonded in a molecule, they usually use a...

<p>structural formula</p> Signup and view all the answers

In the term trace element, what does the adjective trace mean?

<p>The element is required in very small amounts.</p> Signup and view all the answers

Compared with 31P, what does the radioactive isotope 32P have?

<p>One more neutron.</p> Signup and view all the answers

What causes the reactivity of an atom?

<p>The existence of unpaired electrons in the valence shell.</p> Signup and view all the answers

What is true of all atoms that are anions?

<p>The atom has more electrons than protons.</p> Signup and view all the answers

What describes any chemical reaction that has reached equilibrium?

<p>The rates of the forward and reverse reactions are equal.</p> Signup and view all the answers

How can we represent atoms using protons, neutrons, and electrons?

<p>We use notation like 2p+, 2n0, 2e- for helium.</p> Signup and view all the answers

Based on the number of valence electrons, what is the molecular formula of the compound formed by sulfur and hydrogen?

<p>H2S.</p> Signup and view all the answers

What coefficients must be placed in the following equation: C6H12O6 → _____ C2H6O + _____ CO2?

<p>2; 2</p> Signup and view all the answers

What bonds can form between atoms of equal electronegativity?

<p>Van der Waals interactions.</p> Signup and view all the answers

What does the term electron orbital describe?

<p>A three-dimensional space where an electron can be found 90% of the time.</p> Signup and view all the answers

Which statement about the relative potential energy of electrons is correct?

<p>An electron in the 3p orbital has more potential energy than in the 2p orbital.</p> Signup and view all the answers

What is true about weak bonds?

<p>Weak bonds are transient and easily reversible.</p> Signup and view all the answers

What happens when two atoms form a chemical bond?

<p>They transfer or share outer electrons to complete their outer shells.</p> Signup and view all the answers

What are undersea deposits that contain metals such as copper, gold, and silver collectively known as?

<p>Massive sulfides.</p> Signup and view all the answers

What discovery led to a drastic change in deep-sea mining?

<p>Black smokers.</p> Signup and view all the answers

Where would likely be the best place to look for deep sea metal deposits?

<p>Near volcanic fissures.</p> Signup and view all the answers

What is true about ores found in seabeds?

<p>They often have substantially higher purities than those found on land.</p> Signup and view all the answers

Where should a mining company looking to export metals to the country that consumes the most copper and gold target?

<p>China.</p> Signup and view all the answers

Match these prefixes, suffixes, and word roots with their definitions:

<p>co- = with or together with non- = not ios- = equal poly- = many quad- (or quat-) = four anti- = against di- = two prim- = first mono- = single tri- = three</p> Signup and view all the answers

Match these prefixes, suffixes, and word roots with their definitions:

<p>proto- = first hydro- = water neutr- = of neither gender or type lip- = fat -phob = to fear -lysis = loosening, split apart ad- = to -phil = to love de- = from, out of, remove</p> Signup and view all the answers

A substance that cannot be broken down into other substances by ordinary chemical procedures is a(n) _____.

<p>Element.</p> Signup and view all the answers

Which of the following is a trace element required by most living organisms?

<p>Magnesium.</p> Signup and view all the answers

What accounts for the high percentage of oxygen (65.0%) in the human body?

<p>The human body is made up mainly of water.</p> Signup and view all the answers

Which four elements make up approximately 96 percent of living matter?

<p>Carbon, hydrogen, nitrogen, oxygen.</p> Signup and view all the answers

Which trace element is required by humans and other vertebrates but not by other organisms?

<p>Iodine.</p> Signup and view all the answers

All life requires the same essential elements.

<p>False</p> Signup and view all the answers

Which of the following are compounds?

<p>H2O and CH4, but not O2.</p> Signup and view all the answers

What is the mass number of an ion with 109 electrons, 159 neutrons, and a +1 charge?

<ol start="269"> <li></li> </ol> Signup and view all the answers

Match each property to the appropriate subatomic particle:

<p>Proton = Symbol P, +1 charge Neutron = Symbol N, 0 charge Electron = Symbol e, -1 charge</p> Signup and view all the answers

Sort the subatomic particles according to their masses:

<p>mass of ~1 amu = Neutron &amp; Proton mass of ~1/2000 = Electron</p> Signup and view all the answers

What is the atomic number of an atom with 6 protons?

<ol start="6"> <li></li> </ol> Signup and view all the answers

Which term refers to atoms with the same atomic number but different atomic masses?

<p>Isotopes.</p> Signup and view all the answers

Fluorine's atomic number is 9 and its atomic mass is 19. How many neutrons does fluorine have?

<ol start="10"> <li></li> </ol> Signup and view all the answers

An uncharged atom of boron has an atomic number of 5 and an atomic mass of 11. How many protons does boron have?

<ol start="5"> <li></li> </ol> Signup and view all the answers

The innermost electron shell of an atom can hold up to _____ electrons.

<ol start="2"> <li></li> </ol> Signup and view all the answers

In an uncharged atom, the number of protons is equal to the number of electrons.

<p>False</p> Signup and view all the answers

What determines the types of chemical reactions an atom participates in?

<p>The number of electrons in the outermost electron shell.</p> Signup and view all the answers

Which subatomic particle always has a positive charge?

<p>Proton.</p> Signup and view all the answers

Changing the number of _____ would change an atom into an atom of a different element.

<p>Protons in an atom.</p> Signup and view all the answers

The atoms of different phosphorus isotopes _____.

<p>Have different numbers of neutrons.</p> Signup and view all the answers

The type of bonding and the number of covalent bonds an atom can form are determined by _____.

<p>The number of unpaired electrons in the valence shell.</p> Signup and view all the answers

What is the mass number of an atom if its atomic number is 7 and it has 8 neutrons?

<ol start="15"> <li></li> </ol> Signup and view all the answers

Which statement is true of atoms?

<p>Electrons determine the atom's size.</p> Signup and view all the answers

Dr. Jones claims an atom has 3 electrons in the first shell. What should someone tell Dr. Jones?

<p>The first shell shouldn't have 3 electrons.</p> Signup and view all the answers

Which statement is true of the energy levels of electrons in shells?

<p>The valence shell has higher energy than other occupied shells.</p> Signup and view all the answers

What is true of the atom shown in the diagram?

<p>The atom has more than one valence electron.</p> Signup and view all the answers

Two atoms always represent the same element if they have _____.

<p>The same number of protons.</p> Signup and view all the answers

An atom has 6 electrons, 6 protons, and 6 neutrons. You can tell that this atom belongs to the element _____ because _____________________.

<p>C; it has 6 protons.</p> Signup and view all the answers

An atom has 8 protons, 8 neutrons, and 8 electrons. Another isotope of the same element might have _____.

<p>10 neutrons.</p> Signup and view all the answers

Radioactive decay is likely to occur when...

<p>An atom has too many neutrons.</p> Signup and view all the answers

What model most accurately represents the current view of the structure of the atom?

<p>Probability model.</p> Signup and view all the answers

Which statement explains why chemists assign atoms to chemical elements by counting protons?

<p>Elements are defined by the number of protons.</p> Signup and view all the answers

How many half-lives correspond to the fraction 1/2?

<ol> <li></li> </ol> Signup and view all the answers

What represents the fraction of isotope remaining in a fossil at 10 half-lives?

<p>1/1024.</p> Signup and view all the answers

To calibrate the x-axis for 14C decay, how many years make up 5 half-lives?

<p>28,650 years.</p> Signup and view all the answers

If the Neanderthal fossil has approximately 7.80 × 10^-3 of 14C, how many half-lives have passed since the Neanderthal died?

<p>7 half-lives.</p> Signup and view all the answers

Using the 14C calibration, what is the approximate age of the Neanderthal fossil?

<p>40,110 years old.</p> Signup and view all the answers

When did Neanderthals become extinct at this location according to the study?

<p>40,110 years ago or less.</p> Signup and view all the answers

What does the evidence suggest about the overlap of Neanderthals and modern humans in the region?

<p>They may have lived in the same region for up to approximately 2,000 years.</p> Signup and view all the answers

Can 14C be used to date dinosaur bones?

<p>No.</p> Signup and view all the answers

Could radioactive uranium-235 be used to date dinosaur fossils?

<p>Yes.</p> Signup and view all the answers

Knowing the atomic mass of an element allows inferences about what?

<p>The number of protons plus neutrons in the element.</p> Signup and view all the answers

In what way are elements in the same column of the periodic table similar?

<p>They have the same number of electrons in their valence shells when neutral.</p> Signup and view all the answers

Molybdenum has an atomic number of 42. What can be true about molybdenum atoms?

<p>Molybdenum atoms can have between 50 and 58 neutrons.</p> Signup and view all the answers

Why is the average atomic mass of carbon slightly more than 12 daltons?

<p>Some carbon atoms in nature have more neutrons.</p> Signup and view all the answers

What describes the relationship between Atom 1 (1H1) and Atom 2 (3H1)?

<p>They are isotopes.</p> Signup and view all the answers

Nitrogen-15 has a greater mass number than nitrogen-14 because its atomic nucleus contains what?

<p>8 neutrons.</p> Signup and view all the answers

From its atomic number of 15, what can be predicted about the phosphorus atom?

<p>It has 15 protons and 15 electrons.</p> Signup and view all the answers

How many neutrons are present in a phosphorus-32 (32P) atom?

<ol start="17"> <li></li> </ol> Signup and view all the answers

How many electrons will a single atom of sulfur with no charge and no bonds have in its valence shell?

<ol start="6"> <li></li> </ol> Signup and view all the answers

Which element exhibits chemical behavior most like that of oxygen?

<p>Sulfur.</p> Signup and view all the answers

Which atom would most likely form a cation with a charge of +1?

<p>The atom with 1st shell: two e-, 2nd shell: one e-.</p> Signup and view all the answers

Which atom would most likely form an anion with a charge of -1?

<p>The atom with 1st shell: two e-, 2nd shell: seven e-.</p> Signup and view all the answers

What is the atomic mass of an oxygen atom if it commonly has a mass number of 16?

<p>Approximately 16 daltons.</p> Signup and view all the answers

If you change the number of neutrons in an atom, what do you create?

<p>An isotope.</p> Signup and view all the answers

The atomic mass of an element can vary.

<p>False</p> Signup and view all the answers

What is the best description of an atom's physical structure?

<p>Atoms are little bubbles of space with mass concentrated at the center.</p> Signup and view all the answers

What type of bond is joining the two hydrogen atoms?

<p>Covalent.</p> Signup and view all the answers

A(n) _____ refers to two or more atoms held together by covalent bonds.

<p>Molecule.</p> Signup and view all the answers

How many single covalent bond(s) can this atom form?

<ol start="4"> <li></li> </ol> Signup and view all the answers

What type of bond joins the two oxygen atoms?

<p>Double covalent.</p> Signup and view all the answers

Which figure correctly illustrates the nature of the bonding of H2O?

<p>O has 4 electrons bonded to 2 H atoms.</p> Signup and view all the answers

Study Notes

Atomic Structure and Isotopes

  • Trace elements are necessary in minimal quantities for biological functions.
  • Isotope notation includes protons, neutrons, and electrons (e.g., 18O isotope: 8 protons, 10 neutrons, 8 electrons).
  • Atomic number indicates the number of protons in an atom, e.g., sulfur's atomic number is 16.

Chemical Bonds and Reactions

  • Chemical reactivity is influenced by unpaired electrons in an atom's valence shell.
  • Covalent bonds form when atoms share electrons; the type of bonding depends on the number of unpaired electrons.
  • Anions possess more electrons than protons, while cations have fewer electrons.

Equilibrium and Chemical Reactions

  • At chemical equilibrium, the forward and reverse reaction rates are equal.
  • Coefficients in balancing equations indicate the conservation of atoms in a reaction.

Elements and Compounds

  • Elements cannot be broken down into simpler substances; compounds consist of two or more elements combined chemically.
  • Four elements (carbon, hydrogen, nitrogen, oxygen) make up about 96% of living matter.
  • Magnesium and iodine are examples of trace elements that are essential for living organisms.

Radioactive Isotopes and Dating

  • Carbon-14 can be used for dating organic materials up to 75,000 years old; its half-life is 5,730 years.
  • Other isotopes, like uranium-235, can date much older fossils due to a longer half-life.
  • The proportion of 14C in fossils decreases over time, allowing age estimation based on remaining fractions.

Electron Configuration

  • Electrons are organized into shells around the nucleus, with the first shell holding a maximum of 2 electrons.
  • Valence electrons determine an atom's bonding characteristics and reactivity.
  • An atom can have different charges based on electron loss or gain.

Ionic and Covalent Bonds

  • Ionic bonds result from the transfer of electrons between atoms, creating charged ions.
  • Covalent bonds involve shared electrons; single covalent bonds share two electrons, while double bonds share four.
  • Hydrogen bonds occur between polar molecules, particularly those containing hydrogen bonded to electronegative atoms.

Subatomic Particles

  • Protons have a positive charge; neutrons are neutral; electrons have a negative charge.
  • The mass number is the sum of protons and neutrons in the nucleus.
  • Nuclear structure influences the stability and reactivity of an atom.

Miscellaneous Facts

  • The most stable charge for magnesium ions is +2.
  • An atom's behavior is heavily influenced by its electron cloud and arrangement of electrons.
  • Molecular structures can be represented using structural formulas to show how atoms bond together.

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Dive into the key concepts of biology with these flashcards from Chapter 2. Each card presents important terminology and definitions that are crucial for understanding the foundations of biological elements and atomic structure. Perfect for quick review and mastery of the subject matter.

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