Chapter 2: Problem 99
What is the atomic number of the element which has \(3 d^{6}\) as its outermost configuration? (a) 12 (b) 32 (c) 26 (d) 24
Short Answer
Expert verified
The atomic number of the element with a \(3 d^{6}\) outermost configuration is 24.
Step by step solution
01
Understand the Electron Configuration
The given electron configuration, \(3 d^{6}\), means that we are looking at the d-subshell of the 3rd energy level, which has 6 electrons in it.
02
Count the Total Number of Electrons
Since the d-subshell can hold a maximum of 10 electrons and it is part of the 3rd energy level, it is preceded by 2 full earlier energy levels (1s, 2s, 2p). The electron count is 2 (1s) + 8 (2s and 2p) + 6 (3d), which totals to 16 electrons up to 3d-level.
03
Correct the Electron Count for the Full Energy Levels
We missed the 3s and 3p subshells which are also filled before the 3d subshell begins to fill. These account for an additional 2 (3s) + 6 (3p) = 8 electrons. So the total count of electrons becomes 16 (previous count) + 8, which is 24.
04
Determine the Atomic Number
The total number of electrons is also the atomic number of the element, because in a neutral atom the number of protons (which defines the atomic number) is equal to the number of electrons. So, the atomic number of the element is 24.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Electron Configuration
Electron configuration is the distribution of electrons of an atom or molecule in atomic or molecular orbitals. For example, the electron configuration of an element provides a foundational understanding of its properties, reactions, and overall behavior. Let's delve into the electron configuration using the exercise provided.
When we see a configuration like '3d6', this refers to the '3d' subshell of the third energy level having six electrons. Energy levels are like the floors in an apartment building, and the 'd' subshell is like an apartment on the third floor. Just like an apartment can only hold a certain number of people, the 'd' subshell can hold a maximum of ten electrons. The first energy level has only one subshell, the '1s', while the second level has the '2s' and '2p' subshells. These 'rooms' are filled with electrons until they reach capacity before the '3d' begins to fill. If we were to think of the first two full energy levels as foundational courses in school, the '3d' subshell would be the advanced class where only some students reach.
We can further clarify the configuration by counting the electrons in the preceding subshells: 2 in '1s', 2 in '2s', and 6 in '2p' for a total of 10 electrons before even reaching the '3d' subshell. Remember that subshells like '3s' and '3p' come before '3d' and hold 2 and 6 electrons respectively. Essentially, if you're counting floors, don't forget to include the people in the lobby and on other floors before reaching the third. A correct electron count across all these subshells helps us determine the atomic number, which is crucial information for understanding an element's place on the periodic table and its chemical behavior.
When we see a configuration like '3d6', this refers to the '3d' subshell of the third energy level having six electrons. Energy levels are like the floors in an apartment building, and the 'd' subshell is like an apartment on the third floor. Just like an apartment can only hold a certain number of people, the 'd' subshell can hold a maximum of ten electrons. The first energy level has only one subshell, the '1s', while the second level has the '2s' and '2p' subshells. These 'rooms' are filled with electrons until they reach capacity before the '3d' begins to fill. If we were to think of the first two full energy levels as foundational courses in school, the '3d' subshell would be the advanced class where only some students reach.
We can further clarify the configuration by counting the electrons in the preceding subshells: 2 in '1s', 2 in '2s', and 6 in '2p' for a total of 10 electrons before even reaching the '3d' subshell. Remember that subshells like '3s' and '3p' come before '3d' and hold 2 and 6 electrons respectively. Essentially, if you're counting floors, don't forget to include the people in the lobby and on other floors before reaching the third. A correct electron count across all these subshells helps us determine the atomic number, which is crucial information for understanding an element's place on the periodic table and its chemical behavior.
Transition Elements
The transition elements, also known as transition metals, are located in the d-block of the periodic table and include groups 3-12. They are called 'transition' because their properties are transitional between the highly reactive metals of the s-block and the less reactive metals of the p-block.
Characteristics of transition elements include the ability to form colored compounds, multiple oxidation states, and being good conductors of heat and electricity. Their electron configurations are unique in that they have an incomplete d subshell or, in the case of their ions, a d subshell that can either lose or gain electrons easily. This is why they show such a wide range of complex behaviors.
Let's link this to the exercise above. The element with the electron configuration '3d6' is a transition metal. It is halfway through filling up its '3d' subshell and this is reflected in its chemical properties. The variability in the electron arrangements among transition metals helps them form colored compounds and exhibit differences in magnetism and reactivity. For students, think of transition metals as a party where guests can wear different outfits and contribute to the vibe in various ways — this is akin to the multiple oxidation states and the colorful chemistry they exhibit.
Characteristics of transition elements include the ability to form colored compounds, multiple oxidation states, and being good conductors of heat and electricity. Their electron configurations are unique in that they have an incomplete d subshell or, in the case of their ions, a d subshell that can either lose or gain electrons easily. This is why they show such a wide range of complex behaviors.
Let's link this to the exercise above. The element with the electron configuration '3d6' is a transition metal. It is halfway through filling up its '3d' subshell and this is reflected in its chemical properties. The variability in the electron arrangements among transition metals helps them form colored compounds and exhibit differences in magnetism and reactivity. For students, think of transition metals as a party where guests can wear different outfits and contribute to the vibe in various ways — this is akin to the multiple oxidation states and the colorful chemistry they exhibit.
Periodic Table
The periodic table is the grand map of elements, created to categorize the elements according to their chemical properties, which are periodic functions of their atomic numbers. It is organized in rows (periods) and columns (groups or families), with each element assigned a unique box featuring its atomic number, chemical symbol, and atomic mass.
Different regions of the periodic table represent elements with different properties. For instance, the left-most sides are metals, the upper right sides are nonmetals, and along the staircase starting at Boron, we find metalloids, which have properties of both metals and nonmetals. The d-block, where our transition metals reside, is in the center of the table and is fundamental in linking the s-block on the left to the p-block on the right.
Returning to our exercise, identifying the atomic number as 24 places our element, which is Chromium (Cr), in the 6th group of the 4th period. Elements in the same group often share similar properties, and knowing its position helps predict how it might react with others. Imagine the periodic table as a library, and each element is a book. Just as books are organized according to genres and topics to help you find what you're looking for, the periodic table organizes elements to make it easier to study and predict their behaviors during chemical reactions.
Different regions of the periodic table represent elements with different properties. For instance, the left-most sides are metals, the upper right sides are nonmetals, and along the staircase starting at Boron, we find metalloids, which have properties of both metals and nonmetals. The d-block, where our transition metals reside, is in the center of the table and is fundamental in linking the s-block on the left to the p-block on the right.
Returning to our exercise, identifying the atomic number as 24 places our element, which is Chromium (Cr), in the 6th group of the 4th period. Elements in the same group often share similar properties, and knowing its position helps predict how it might react with others. Imagine the periodic table as a library, and each element is a book. Just as books are organized according to genres and topics to help you find what you're looking for, the periodic table organizes elements to make it easier to study and predict their behaviors during chemical reactions.
