Questions and Answers
A substance that cannot be broken down into other substances by ordinary chemical procedures is a(n) _____.
element
Which atom diagram shows the electron with the highest potential energy?
Electrons are held in an atom by attraction to what particle or location?
Attraction to the positively charged protons in the nucleus
What can happen to an electron when sunlight hits it? (Select all that apply)
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Changing the number of _____ would change an atom into an atom of a different element.
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What type of bond is joining the two hydrogen atoms?
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A(n) _____ refers to two or more atoms held together by covalent bonds.
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This atom can form up to _____ single covalent bond(s).
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A(n) _____ bond joins these two oxygen atoms.
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The brackets are indicating a(n) _____ bond.
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What name is given to the bond between water molecules?
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Atoms with the same number of protons but with different electrical charges _____
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In salt, what is the nature of the bond between sodium and chlorine?
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An ionic bond involves _____
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What type of bond joins the carbon atom to each of the hydrogen atoms?
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Covalent bonds hold atoms together because they...
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In molecules, C, H, O, and N atoms usually make __, __, __, and __ bonds respectively.
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An atom's atomic number is 7. Its valence is most likely...
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By making two covalent bonds, an O atom (with 8 protons) fills its valence shell. Why does the atom's charge stay close to zero?
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In a double covalent bond, a carbon atom shares...
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The ammonia molecule in the diagram has the observed bond orientation because...
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Without making or breaking bonds, the pictured molecule can change its shape because...
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Two C atoms form a double bond. Each C is bound to two H atoms. Which statement is true?
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Partial charges occur when...
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To fill the valence shell, an electrically neutral, unbonded atom with atomic number 8 must add...
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Which answer helps to explain why carbon atoms tend to make 4 covalent bonds?
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An electrically neutral molecule has the formula C3H4O2N. If the carbon atoms form the usual number of bonds, how many covalent bonds will each hydrogen atom have with other atoms in the molecule?
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Chemical equilibrium is reached when _____
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The atomic number of sulfur is 16. Sulfur combines with hydrogen by covalent bonding to form a compound, hydrogen sulfide. Based on the number of valence electrons in a sulfur atom, predict the molecular formula of the compound.
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What happens when two atoms form a chemical bond?
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Which statement about weak bonds is correct?
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Study Notes
Elements and Atoms
- An element is a fundamental substance that cannot be broken down into simpler substances through ordinary chemical procedures.
- Atoms are held together by the attraction between electrons and positively charged protons in the nucleus.
Electron Behavior
- Electrons can absorb sunlight, enabling them to move to a higher electron shell or remain in their original shell.
- When an electron gains energy, it transitions from a lower to a higher shell; losing energy prompts movement from a higher to a lower shell.
Subatomic Particles and Bonds
- Changing the number of protons in an atom alters it into a different element.
- Covalent bonds occur when atoms share electrons; for example, two hydrogen atoms form a covalent bond.
- A molecule is defined as two or more atoms bonded covalently.
Bonding Details
- An atom can form up to four single covalent bonds and typically forms a double covalent bond with another element like oxygen.
- Ionic bonds are formed between charged particles like sodium and chlorine, characterized by attraction between ions of opposite charges.
Molecular Structure and Charge
- Water molecules exhibit hydrogen bonds, responsible for many of water's unique properties.
- Ions with the same number of protons but different charges are classified as different ions.
Covalent Bonding Characteristics
- Single covalent bonds involve shared electrons. Carbon usually makes four bonds, while hydrogen, oxygen, and nitrogen typically make one, two, and three bonds, respectively.
- The atomic number reveals the number of protons; an atom with atomic number 8 needs two additional electrons to complete its valence shell.
Chemical Equilibrium
- Chemical equilibrium is achieved when forward and reverse reactions occur at the same rate, leading to stable concentrations of reactants and products.
Structural Flexibility
- Molecules can change shape without breaking bonds due to rotation around single bonds.
Weak Bonds
- Weak bonds are typically transient and easily reversible, playing a crucial role in molecular interactions.
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Description
Test your knowledge of fundamental concepts from Biology Chapter 2 with these flashcards. Each card focuses on essential terms and definitions including elements and atomic structure. Perfect for review or preparation for exams.
