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Questions and Answers
In the term trace element, what does the adjective trace mean?
In the term trace element, what does the adjective trace mean?
The element is required in very small amounts.
Compared with 31P, what does the radioactive isotope 32P have?
Compared with 31P, what does the radioactive isotope 32P have?
One more neutron.
What gives rise to the reactivity of an atom?
What gives rise to the reactivity of an atom?
The existence of unpaired electrons in the valence shell.
True or False: All atoms that are anions have more electrons than protons.
True or False: All atoms that are anions have more electrons than protons.
What does equilibrium in a chemical reaction mean?
What does equilibrium in a chemical reaction mean?
Which notation represents the 18O isotope of oxygen?
Which notation represents the 18O isotope of oxygen?
What is the molecular formula for hydrogen sulfide formed by sulfur combining with hydrogen?
What is the molecular formula for hydrogen sulfide formed by sulfur combining with hydrogen?
What coefficients must be placed in the following reaction: C6H12O6 S _____ C2H6O + _____ CO2?
What coefficients must be placed in the following reaction: C6H12O6 S _____ C2H6O + _____ CO2?
What is true regarding essential elements and living organisms?
What is true regarding essential elements and living organisms?
True or False: Concentrations of trace elements above what is required generally have no effect on organisms.
True or False: Concentrations of trace elements above what is required generally have no effect on organisms.
True or False: Compounds containing oxygen are not greenhouse gases.
True or False: Compounds containing oxygen are not greenhouse gases.
There are __________ naturally occurring elements.
There are __________ naturally occurring elements.
What is a trace element?
What is a trace element?
What are the four most abundant elements found in living systems?
What are the four most abundant elements found in living systems?
Which of the following has negligible mass?
Which of the following has negligible mass?
Which subatomic particle has appreciable mass and lacks a charge?
Which subatomic particle has appreciable mass and lacks a charge?
The number of protons in an uncharged atom __________.
The number of protons in an uncharged atom __________.
An element has eight protons, nine neutrons, and eight electrons. Its atomic number and atomic mass, respectively, are __________.
An element has eight protons, nine neutrons, and eight electrons. Its atomic number and atomic mass, respectively, are __________.
An uncharged atom of nitrogen (atomic number = 7) has __________.
An uncharged atom of nitrogen (atomic number = 7) has __________.
In which of the following will isotopes of an element always differ?
In which of the following will isotopes of an element always differ?
A particular carbon isotope has an atomic number of 6 and an atomic mass of 14. The respective number of neutrons, protons, and electrons that this carbon isotope has is __________.
A particular carbon isotope has an atomic number of 6 and an atomic mass of 14. The respective number of neutrons, protons, and electrons that this carbon isotope has is __________.
Phosphorus-32 (radioactive) has __________ than phosphorus-35 (normal).
Phosphorus-32 (radioactive) has __________ than phosphorus-35 (normal).
What would be an isotope of calcium?
What would be an isotope of calcium?
Why are radioactive isotopes useful in scientific research?
Why are radioactive isotopes useful in scientific research?
A neutral atom of chlorine has an atomic number of 17. It has __________ electrons in its third shell.
A neutral atom of chlorine has an atomic number of 17. It has __________ electrons in its third shell.
The chemical characteristics or reactivity of an element depend mostly on the __________.
The chemical characteristics or reactivity of an element depend mostly on the __________.
These similarities in chemical properties result when different elements have similar __________.
These similarities in chemical properties result when different elements have similar __________.
How many electrons would be present in the valence shell of a sulfur atom (atomic number 16, mass number 32)?
How many electrons would be present in the valence shell of a sulfur atom (atomic number 16, mass number 32)?
For most atoms, when is a stable configuration of electrons attained?
For most atoms, when is a stable configuration of electrons attained?
An atom that normally has __________ in its outer shell would NOT tend to form chemical bonds with other atoms.
An atom that normally has __________ in its outer shell would NOT tend to form chemical bonds with other atoms.
Consider a hypothetical atom with an atomic number of 4 and a net charge of +1. How many neutrons does this ion have?
Consider a hypothetical atom with an atomic number of 4 and a net charge of +1. How many neutrons does this ion have?
When pairs of valence electrons are shared by two neutral atoms, what type of bond is formed?
When pairs of valence electrons are shared by two neutral atoms, what type of bond is formed?
A covalent bond is likely to be polar if __________.
A covalent bond is likely to be polar if __________.
When the proton number and electron number are unequal, the atom or molecule __________.
When the proton number and electron number are unequal, the atom or molecule __________.
What would result if an uncharged copper atom lost two electrons?
What would result if an uncharged copper atom lost two electrons?
What charge would you expect on the sulfate ion after ionization of CaSO4?
What charge would you expect on the sulfate ion after ionization of CaSO4?
Ionic bonds form as a result of __________.
Ionic bonds form as a result of __________.
A hydrogen bond __________.
A hydrogen bond __________.
When do hydrogen bonds occur?
When do hydrogen bonds occur?
What is the role of van der Waals interactions in biological molecules?
What is the role of van der Waals interactions in biological molecules?
Which molecule has the shape of a completed tetrahedron?
Which molecule has the shape of a completed tetrahedron?
What chemical property of a molecule is most important for blocking receptor proteins?
What chemical property of a molecule is most important for blocking receptor proteins?
Which statement is true about chemical reactions?
Which statement is true about chemical reactions?
What characterizes a reversible reaction that has reached chemical equilibrium?
What characterizes a reversible reaction that has reached chemical equilibrium?
How many electrons are involved in a single covalent bond?
How many electrons are involved in a single covalent bond?
In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by _____.
In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by _____.
Why do Minneapolis and Portland have different climates despite being at the same latitude?
Why do Minneapolis and Portland have different climates despite being at the same latitude?
If you change the number of neutrons in an atom, what do you create?
If you change the number of neutrons in an atom, what do you create?
Which of the following can be attributed to water's high specific heat?
Which of the following can be attributed to water's high specific heat?
Study Notes
Trace Elements and Isotopes
- Trace elements are required by organisms in very small amounts.
- The radioactive isotope 32P has one more neutron than 31P.
- Isotopes of the same element differ in atomic mass and neutron count.
Atomic Structure and Behavior
- Reactivity of an atom is due to unpaired electrons in its valence shell.
- Anions have more electrons than protons, leading to a negative charge.
- The atomic number indicates the number of protons, while atomic mass is the sum of protons and neutrons.
Chemical Reactions and Equilibrium
- Chemical reactions at equilibrium have equal rates for forward and reverse reactions.
- The law of conservation of mass dictates that all atoms are accounted for in chemical reactions.
Essential Elements in Biology
- Essential elements vary across life forms, but all require elements like iron.
- Naturally occurring elements total 92, with only a few being considered trace elements.
Electrons and Chemical Bonds
- Electrons largely determine atomic reactivity and bonding behaviors.
- For most atoms, a stable electron configuration is achieved with eight electrons in the outermost shell.
- A covalent bond forms when pairs of valence electrons are shared between atoms.
Ionic and Hydrogen Bonds
- Ionic bonds arise from the attraction of oppositely charged ions.
- Hydrogen bonds are weak and occur due to partial charges.
- Van der Waals interactions help stabilize biological molecule structures despite being weak.
Molecular Geometry and Properties
- The molecular shape, such as a tetrahedron in methane (CH4), is pivotal in biological interactions.
- Water’s high specific heat allows it to absorb heat without significant temperature changes, affecting local climates.
Isotopes and Radioactive Applications
- Radioactive isotopes, like phosphorus-32, are used in research to trace metabolic pathways in organisms.
- Changing the number of neutrons in an atom creates isotopes, which can have varied stability and utility in scientific contexts.
Key Biological Concepts
- The number of protons in a neutral atom equals the number of electrons, maintaining charge balance.
- Compounds can exhibit emergent properties, which may differ significantly from their elemental components.
Additional Facts
- Electrons have negligible mass compared to protons and neutrons, which have appreciable mass.
- Sulfur has six valence electrons, risking similar chemical behavior with elements that share similar outer-shell electron configurations.
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Description
Test your knowledge with these practice questions from Biology Chapter 2. This quiz covers essential concepts including trace elements, isotopes, and atomic reactivity. Challenge yourself to see how well you understand the material!
