Question 1
In a chemistry lab, a student is filling electron orbitals for different sublevels. What is the most electrons they can place in one -sublevel according to the electron configuration rules?No clue? Show me the answer
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Method #1Memorization of Sublevel CapacitiesStep 1: Determine which sublevel's capacity is needed
The problem asks for the maximum electron count for a single -sublevel. In electron configuration, each sublevel type () has a specific electron capacity.
Step 2: Remember electron capacities of sublevels
In studying Atomic Structure and Electronic Configuration, it's important to recall the maximum electron count for each sublevel. The typical capacities are: -sublevel: , -sublevel: , -sublevel: , -sublevel: .
Step 3: Disregard Option A
Option A lists electrons, which is the capacity for an -sublevel, not a -sublevel.
Step 4: Disregard Option B
Option B lists electrons, which matches the capacity for a -sublevel.
Step 5: Disregard Option D
Option D lists electrons, which is the capacity of an -sublevel.
Step 6: Verify the correct choice
Based on memorized capacities, a -sublevel holds up to electrons, which aligns with Option C.
Method #2Orbital MultiplicationStep 1: Define the task at hand
The task is to find the maximum number of electrons that can fit in a -sublevel. To solve this, we need to know the number of orbitals in that sublevel.
Step 2: Count the number of orbitals in each sublevel
In the structure of atoms, sublevels contain a specific, odd number of orbitals: -sublevel: orbital, -sublevel: orbitals, -sublevel: orbitals, -sublevel: orbitals.
Step 3: Use the Pauli Exclusion Principle
The Pauli Exclusion Principle states that each orbital can hold up to electrons with opposite spins. This is true for any orbital, regardless of the sublevel it belongs to.
Step 4: Calculate the total electron capacity
Multiply the number of orbitals by the number of electrons per orbital:
Step 5: Exclude wrong options and verify
Review the options to confirm: * Option A is wrong: is for an -sublevel. * Option B is wrong: is for a -sublevel. * Option D is wrong: is for an -sublevel. Our calculation confirms Option C is correct.
Method #3Periodic Table Block AnalysisStep 1: Determine the question focus
The question is about the maximum electrons in a -sublevel, which can be determined from the -block of the Periodic Table.
Step 2: Identify where the d-block is located
On the Periodic Table, elements are grouped into blocks by the sublevel being filled with electrons. The -block, containing transition metals, is centrally located (Groups 3-12).
Step 3: Link the block's width to electron count
Per the Aufbau principle, moving across a period adds one proton to the nucleus and one electron to the valence shell. Therefore, the number of elements in a block matches the maximum electrons the sublevel can hold.
Step 4: Count elements in a d-block row
For a row in the -block (e.g., Period 4), count: Scandium (Sc), Titanium (Ti), Vanadium (V), Chromium (Cr), Manganese (Mn), Iron (Fe), Cobalt (Co), Nickel (Ni), Copper (Cu), Zinc (Zn). There are 10 elements across.
Step 5: Discard incorrect answers
Using other block widths: * Option A: 2 electrons fit an -block. * Option B: 6 electrons fit a -block. * Option D: 14 electrons fit an -block.
Step 6: Confirm correct choice
The -block spans 10 elements, so a -sublevel holds 10 electrons.
Method #4Quantum Number FormulaStep 1: Select the correct quantum number
To find the electron capacity of a -sublevel, identify its angular momentum quantum number (). The values are: -sublevel: , -sublevel: , -sublevel: , -sublevel: . Use for the -sublevel.
Step 2: Use the formula for electron capacity
The formula to calculate maximum electrons is: . Here, indicates the number of orbitals in the sublevel, and shows the max electrons each orbital can have (Pauli Exclusion Principle).
Step 3: Compute the electron capacity
Insert for the -sublevel into the formula: . This calculation shows a -sublevel has 5 orbitals, each holding 2 electrons.
Step 4: Discard wrong options
Verify other options: * Option A (2): Matches an -sublevel (). * Option B (6): Matches a -sublevel (). * Option D (14): Matches an -sublevel ().
Step 5: State the correct answer
The quantum number formula confirms a -sublevel can hold 10 electrons, matching Option C.
Question 2
Imagine you're watching a chemistry demonstration where a small piece of sodium is dropped into a beaker of water. What products are formed from this reaction?No clue? Show me the answer
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Method #1Direct Recall of Chemical EquationStep 1: Remember the reactivity of Group 1 elements
In the periodic table, Group 1 elements like Lithium, Sodium, and Potassium are known for their high reactivity due to a single electron in their outer shell. When they come into contact with water, they react very energetically.
Step 2: Express the typical reaction equation
When an alkali metal () reacts with water, the standard equation is: This equation indicates that the reaction produces a metal hydroxide and hydrogen gas.
Step 3: Disregard Option A
While alkali metals do form oxides when reacting with oxygen, their interaction with water results in hydroxides, not oxides, and doesn't release oxygen gas.
Step 4: Disregard Option B
Group 1 metals are famously highly reactive with water. For instance, Potassium reacts so intensely that the hydrogen it produces often catches fire, burning with a lilac flame.
Step 5: Disregard Option C
The phrase "metal acid" is a misconception. The resulting is a strong base, which is why these are termed "alkali metals."
Step 6: Confirm the correct solution
According to the general equation, the reaction yields a metal hydroxide and hydrogen gas, corresponding to the description in Option D.
Method #2Process of EliminationStep 1: Consider the reactivity of metals
To tackle this, recall that Group 1 alkali metals (like Lithium, Sodium, and Potassium) are extremely reactive due to having one electron in their outer shell, which is easily lost.
Step 2: Assess the claim of non-reactivity
In lab settings, metals like sodium or potassium react vigorously on contact with water. Due to their high reactivity, they are stored under oil to prevent accidental reactions with air moisture. Thus, any option suggesting no reaction can be excluded.
Step 3: Determine the type of solution formed
The name "Alkali metals" hints at their ability to create a basic solution upon reacting with water. These metals don't form acids, so options suggesting acid formation can be disregarded.
Step 4: Identify the gas evolved
During the reaction, gas bubbles form, and the gas can be identified by the "squeaky pop" test with a lit splint, confirming it as hydrogen gas (). Oxygen gas would reignite a glowing splint, and the metals form hydroxides instead of oxides in water.
Step 5: Choose the correct reaction description
By eliminating the options involving no reaction, acid formation, and oxygen gas, the remaining chemical equation for this reaction (where is the alkali metal) is: This verifies that the products are a metal hydroxide and hydrogen gas.
Question 3
In a chemistry experiment, a student observes that the outermost electrons of certain elements occupy the s subshell. What might their electron configurations conclude with, if not ?No clue? Show me the answer
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Method #1Periodic Table Block IdentificationStep 1: Locate the s-block on the periodic table
Elements are arranged in the periodic table into blocks (s, p, d, and f) based on the subshell being filled by their outermost electrons. The s-block includes the first two columns: Group 1 and Group 2, along with Helium.
Step 2: Examine Group 1's electron setup
The s-subshell features a single orbital capable of accommodating two electrons. Elements in Group 1, like Lithium and Sodium, hold one electron in their outer s-subshell, resulting in a typical configuration of:
Step 3: Inspect Group 2's electron setup
For elements in Group 2, such as Beryllium and Magnesium, an additional electron fills the s-subshell to its maximum. Consequently, their electron configuration terminates with:
Step 4: Rule out options not fitting the s-block
AConsider why these don't suit the s-block: - Option A () is linked to the f-block (lanthanides and actinides). - Option C () corresponds to the d-block (transition metals). - Option D () is associated with the start of the p-block (Group 13).
Step 5: Verify the correct choice
With the s-block only comprising two groups, the electron configuration of an s-block element can only conclude with or .
Method #2Elimination by Subshell TypeStep 1: Understand the s-block rule
For elements in the s-block, their outermost electrons reside in an s-subshell, meaning any valid configuration must end with ''.
Step 2: Dismiss non-s subshells
AWe're looking solely for s-subshell endings, so we dismiss any configurations ending in , , or subshells, as these belong to different blocks: - Option A with an -subshell () is of the f-block. - Option C with a -subshell () is of the d-block. - Option D with a -subshell () is of the p-block.
Step 3: Identify the s-block answer
After eliminating , , and subshell options, the remaining choice with an s-subshell is correct. The s-subshell can hold up to 2 electrons, with for Group 1 and for Group 2.
Method #3Orbital Capacity PrincipleStep 1: Recognize the focus on the s-block
The focus is on the s-block of the periodic table, which includes elements in Group 1 and Group 2, plus Helium, where the outer electrons fill an s-subshell.
Step 2: Use orbital capacity to find configurations
To determine configurations, consider the s-subshell capacity: 1. An s-subshell has one orbital. 2. By the Pauli Exclusion Principle, one orbital can contain two electrons. Therefore, possible configurations are: - (one electron) - (two electrons)
Step 3: Exclude non-s possibilities
The question is about the s-block, so any configurations with , , or subshells for outer electrons must be incorrect.
Step 4: Conclude with the correct configuration
With typical for alkali metals, the only other s-block configuration occurs when the orbital is full, resulting in , as seen in alkaline earth metals and helium.
Question 4
A student is examining a bromine () atom in its ground state, which is placed in the 4th row and 17th column of the periodic table. What is the highest principal quantum number () where electrons are found in this atom?No clue? Show me the answer
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Method #1Period Number MethodStep 1: Locate the position of Bromine
Using the Period Number Method, start by identifying bromine's () spot on the periodic table. As mentioned, bromine is situated in the 4th period.
Step 2: Connect period with energy level
When exploring the periodic table's structure, it's important to note that the period number shows the highest principal energy level () that contains electrons in an atom's ground state. As bromine is in the 4th period, its electrons extend up to the 4th principal energy level ().
Step 3: Discard incorrect answers
B1Since bromine's maximum energy level is , options can be dismissed as follows: * Option 1 and 2: Levels 1 and 2 must fill up before reaching level 4. * Option 3: Though level 3 accommodates electrons (like the subshell), it isn't the highest level in period 4.
Step 4: Verify the right choice
With bromine being in period 4, the top principal energy level with electrons is . This is validated by its electron configuration: The number "4" in and signifies the principal energy level.
Method #2Electron Configuration MethodStep 1: Determine the atomic number
To find the electron setup, first, locate bromine's atomic number () on the periodic table. It's in the 4th period and 17th group, with atomic number 35, meaning it has 35 electrons in a neutral ground-state atom.
Step 2: Create electron configuration
Following the Aufbau principle, orbitals are filled in order of rising energy: . Bromine's () full electron configuration is: Alternatively, the condensed form using Argon is:
Step 3: Identify highest principal level
In electron configurations, the leading numbers before subshells (like the 4 in and ) denote the principal quantum number (), showing the principal energy level. Reviewing the configuration: - Electrons are in levels , and . - Despite filling after , the largest coefficient is 4.
Step 4: Rule out incorrect choices
B1Based on the highest value found, assess the options: * Option 1 (1): This is the lowest energy level, not the top. * Option 2 (2): Electrons are here, but it's not the highest level. * Option 3 (3): Although the subshell has many electrons, the and subshells are in a higher principal level ().
Step 5: Select the correct option
Bromine's placement in period 4 indicates its valence electrons are in level. Thus, the highest principal energy level with electrons is 4.
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