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Intro to Chemistry: Atomic Structure, Bonding, and Nomenclature Practice

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Study Guide - Smart Notes

Tailored notes based on your materials, expanded with key definitions, examples, and context.

Q1. A sodium ion, Na+, has the same electron configuration as a(n):

Background

Topic: Electron Configuration & Isoelectronic Species

This question tests your understanding of how ions gain or lose electrons to achieve the same electron configuration as noble gases or other atoms/ions.

Key Terms:

  • Electron configuration: The arrangement of electrons in an atom or ion.

  • Isoelectronic: Having the same number of electrons (and thus the same electron configuration) as another atom or ion.

Step-by-Step Guidance

  1. Recall that a neutral sodium atom (Na) has 11 electrons. When it loses one electron to become Na+, it has 10 electrons.

  2. Determine which atom or ion also has 10 electrons. Consider the atomic numbers of the options provided.

  3. Compare the electron configurations of Na+ and the other species to see which matches.

Try solving on your own before revealing the answer!

Q2. The number of electrons in a chloride ion, Cl-, is:

Background

Topic: Ions and Electron Counting

This question checks your ability to determine the number of electrons in an ion, given its atomic number and charge.

Key Terms:

  • Chlorine atom (Cl): Atomic number 17 (so 17 protons and 17 electrons in the neutral atom).

  • Chloride ion (Cl-): Has gained one electron compared to the neutral atom.

Step-by-Step Guidance

  1. Start with the atomic number of chlorine to find the number of electrons in a neutral atom.

  2. Since the ion has a -1 charge, add one electron to the neutral atom's count.

  3. Write out the calculation for the total number of electrons in Cl-.

Try solving on your own before revealing the answer!

Q3. When barium reacts with iodine, barium ions (Ba2+) and iodide ions (I-) are formed. In this reaction, iodine atoms:

Background

Topic: Redox Reactions & Ion Formation

This question tests your understanding of how atoms gain or lose electrons during ionic bond formation.

Key Terms:

  • Oxidation: Loss of electrons.

  • Reduction: Gain of electrons.

  • Iodine atom (I): Becomes iodide ion (I-) by gaining electrons.

Step-by-Step Guidance

  1. Consider the charge of the iodide ion compared to the neutral iodine atom.

  2. Determine whether electrons are gained or lost to form I- from I.

  3. Relate this process to the definitions of oxidation and reduction.

Try solving on your own before revealing the answer!

Q4. Which of the following pairs is isoelectronic?

Background

Topic: Isoelectronic Species

This question asks you to identify which pair of atoms or ions have the same number of electrons.

Key Terms:

  • Isoelectronic: Species with the same number of electrons.

  • Remember to account for the charge when counting electrons in ions.

Step-by-Step Guidance

  1. Count the number of electrons in each atom or ion in the pairs given.

  2. Compare the electron counts to see which pair matches.

  3. Double-check your math for each option to ensure accuracy.

Try solving on your own before revealing the answer!

Q5. Which is the electron dot structure of magnesium?

Background

Topic: Lewis Dot Structures

This question tests your ability to represent the valence electrons of an element using Lewis dot notation.

Key Terms:

  • Lewis dot structure: A diagram showing valence electrons as dots around the element symbol.

  • Valence electrons: Electrons in the outermost shell of an atom.

Step-by-Step Guidance

  1. Determine the group number of magnesium in the periodic table to find the number of valence electrons.

  2. Draw the symbol for magnesium (Mg) and place the correct number of dots around it to represent the valence electrons.

  3. Compare your drawing to the options provided (or images, if available).

Try solving on your own before revealing the answer!

Q6. Where does an element X with the given electron dot structure fit in the periodic table?

Background

Topic: Periodic Table Groups & Lewis Structures

This question tests your ability to relate the number of valence electrons (shown in the dot structure) to the group number in the periodic table.

Key Terms:

  • Group number: Indicates the number of valence electrons for main group elements.

  • Electron dot structure: Shows the number of valence electrons as dots around the element symbol.

Step-by-Step Guidance

  1. Count the number of dots (valence electrons) in the given structure.

  2. Match this number to the corresponding group in the periodic table (e.g., 1A, 2A, etc.).

  3. Review the group characteristics to confirm your choice.

Try solving on your own before revealing the answer!

Q7. Which of the noble gases does NOT have an octet of electrons in its outer shell?

Background

Topic: Electron Configuration of Noble Gases

This question tests your knowledge of the electron configurations of noble gases and the octet rule.

Key Terms:

  • Octet rule: Atoms tend to have eight electrons in their valence shell (except for some exceptions like helium).

  • Noble gases: Group 18 elements with full valence shells.

Step-by-Step Guidance

  1. Recall the electron configurations for each noble gas listed.

  2. Determine which noble gas does not have eight electrons in its outer shell.

  3. Consider the exceptions to the octet rule among the noble gases.

Try solving on your own before revealing the answer!

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