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Questions and Answers
What is indicated by the number at the top of an element in the periodic table?
What is indicated by the number at the top of an element in the periodic table?
Which group in the periodic table contains elements that have two valence electrons?
Which group in the periodic table contains elements that have two valence electrons?
What do all elements in the same group of the periodic table share in common?
What do all elements in the same group of the periodic table share in common?
What is the primary reason most elements form compounds?
What is the primary reason most elements form compounds?
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What type of bond involves the electrostatic attraction between ions of opposite charge?
What type of bond involves the electrostatic attraction between ions of opposite charge?
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Which of the following statements best describes the valence electrons of elements in group 7?
Which of the following statements best describes the valence electrons of elements in group 7?
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What determines the period number of an element in the periodic table?
What determines the period number of an element in the periodic table?
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In Bohr's theory, what does the energy level of an element correspond to?
In Bohr's theory, what does the energy level of an element correspond to?
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What happens to white light when it passes through a hydrogen gas flask?
What happens to white light when it passes through a hydrogen gas flask?
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What is the highest energy level for an argon atom based on its electron configuration?
What is the highest energy level for an argon atom based on its electron configuration?
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In Bohr's theory, how many electrons can the first shell hold?
In Bohr's theory, how many electrons can the first shell hold?
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Which of the following describes the nature of electrons in relation to energy levels?
Which of the following describes the nature of electrons in relation to energy levels?
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What characterizes the arrangement of elements in the periodic table?
What characterizes the arrangement of elements in the periodic table?
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How many electrons can the second shell hold according to Bohr's theory?
How many electrons can the second shell hold according to Bohr's theory?
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Which statement is true regarding the movement of electrons between energy levels?
Which statement is true regarding the movement of electrons between energy levels?
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Based on the rules for electron configuration, which of the following configurations is correct for magnesium?
Based on the rules for electron configuration, which of the following configurations is correct for magnesium?
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What occurs when two pairs of electrons are shared between two atoms?
What occurs when two pairs of electrons are shared between two atoms?
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What characteristic of polar molecules affects their interaction with non-polar molecules?
What characteristic of polar molecules affects their interaction with non-polar molecules?
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What phenomenon causes hydrogen bonding in water?
What phenomenon causes hydrogen bonding in water?
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How does electronegativity influence the distribution of electrons in a covalent bond?
How does electronegativity influence the distribution of electrons in a covalent bond?
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What is a characteristic feature of compounds with a hydrogen bond?
What is a characteristic feature of compounds with a hydrogen bond?
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Which type of molecule is referred to as hydrophobic?
Which type of molecule is referred to as hydrophobic?
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What type of bond is formed when three pairs of electrons are shared between two atoms?
What type of bond is formed when three pairs of electrons are shared between two atoms?
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What effect does the constant motion of electrons in an atom or molecule create?
What effect does the constant motion of electrons in an atom or molecule create?
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Study Notes
Electron Chemistry
- White light dispersed by prism into component colours
- Passing white light through hydrogen gas produces black lines at specific wavelengths
- Atoms have nucleus surrounded by energy levels/orbitals where electrons exist
- Electrons can only exist within specific orbitals
- Electrons need fixed energy amounts to move between orbitals
- This fixed energy amount is called a quantum/photon
- Energy levels are represented by straight lines, not orbitals as 'planets around the sun'
- The lowest energy level, n=1, is closest to the nucleus
Bohr's Theory
- Electrons occupy the lowest possible energy levels
- First shell holds up to 2 electrons
- Second shell holds up to 8 electrons
- Third shell (and subsequent shells) hold up to 8 electrons
Atomic Configurations
- Example: Argon (atomic number 18) has electronic configuration 2, 8, 8
- Example: Magnesium (atomic number 12) has electronic configuration 2, 8, 2
The Periodic Table
- Tabular arrangement of chemical elements according to atomic number
- Atomic number at top of box
- Mass number at bottom of box
- Elements classified as metals, metalloids, or nonmetals
- Elements in groups have the same number of valence electrons
- Valence electrons: same as group number
Group 1 Elements (Alkali Metals)
- Have one valence electron
- Very reactive
- Form compounds in consistent ratios
Group 2 Elements (Alkaline Earth Metals)
- Have two valence electrons
- Less reactive than Group 1 elements
Group 7 Elements (Halogens)
- Have seven valence electrons
- Reactive, readily gain electrons
Group 8 Elements (Noble Gases)
- Have eight valence electrons
- Relatively unreactive
Periods
- Horizontal rows in the periodic table
- Period number corresponds to number of occupied electron shells
Bonding
- Elements bond to achieve full outer electron shells
-
Ionic bond: electrostatic attraction between oppositely charged ions (metal + nonmetal)
- Example: sodium (Na) and chlorine (Cl) form sodium chloride (NaCl). Sodium loses an electron, becomes positive ion; chlorine gains electron, becomes negative ion
-
Covalent bond: sharing of electron pairs (nonmetal + nonmetal)
- Single, double, or triple covalent bonds depending on shared electron pairs
- Dipole-Dipole attractions: unequal sharing of electrons in covalent bonds creates partial charges, leading to attractions between molecules
- Hydrogen bonding: a strong dipole-dipole attraction involving hydrogen and a highly electronegative atom (e.g., oxygen)
- Van der Waals' Forces: weak attractive forces caused by temporary fluctuations in electron distribution around atoms or molecules
Metallic Bonding
- Consists of an array of cations in a "sea of delocalised electrons"
- Good electrical and thermal conductors because electrons can freely move throughout the structure
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Description
Test your knowledge of electron chemistry, Bohr's theory, and atomic configurations. This quiz covers fundamental concepts including the structure of atoms, energy levels, and the periodic table. Dive into the intricacies of how electrons are arranged around the nucleus and their energy transitions.
