Electron configurations 2 | Electronic structure of atoms | Chemistry | Khan Academy
TLDRThis video explains how to determine the electron configuration for nickel, which has 28 electrons. It starts by detailing the periodic table's s, p, and d blocks and proceeds by filling electrons in increasing energy order: 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, and 3d8. The video compares two methods: using the periodic table directly and using an orbital filling diagram, highlighting the significance of valence electrons in chemical reactions.
Takeaways
- 🔬 Nickel has 28 electrons, which determine its electron configuration.
- 📚 Electrons fill shells and subshells in a specific order: 1s, 2s, 2p, 3s, 3p, 4s, and then 3d.
- 🌐 The s-block, d-block, and p-block refer to the regions of the periodic table where electrons are filled in those subshells.
- 🎨 Electron configurations can be visualized with colors to differentiate between shells and subshells.
- 🔢 Nickel's electron configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁸, following the lowest to highest energy principle.
- ⏳ When filling the d-block, use the period number minus one to determine the correct shell (e.g., 4s² electrons are in the fourth period, but 3d⁸ is filled because 4 - 1 = 3).
- 👀 Valence electrons, those in the outermost shell, are crucial for chemical reactions and can be identified in the electron configuration.
- 🔄 There are two methods to determine electron configuration: using the periodic table or a diagram of energy levels and subshells.
- 📉 The periodic table method builds intuition about element reactivity and positions, while the diagram method is more systematic.
- 🔮 Electrons don't just stay in their shells; they jump between orbitals, though for many purposes, it's useful to consider them as separate.
- 🧠 Understanding electron configurations is fundamental for predicting how elements will interact in chemical reactions.
Q & A
What is the atomic number of nickel?
-The atomic number of nickel is 28, which means it has 28 protons and, in a neutral state, 28 electrons.
How does the electron configuration of nickel begin?
-The electron configuration of nickel begins with filling the 1s orbital with two electrons (1s²).
What is the significance of the superscript '2' in the electron configuration?
-The superscript '2' indicates that two electrons are being placed into a particular subshell or orbital.
How many electrons are in the 2p orbital of nickel?
-There are six electrons in the 2p orbital of nickel (2p⁶).
What is the electron configuration for the third shell of nickel?
-The electron configuration for the third shell of nickel is 3s² 3p⁶.
What is the role of the 4s orbital in the electron configuration of nickel?
-The 4s orbital in the electron configuration of nickel is filled with two electrons (4s²), which is part of the process of filling the fourth shell.
Why do electrons fill the 3d orbitals before the 4s orbital in nickel's electron configuration?
-Electrons fill the 3d orbitals before the 4s orbital in nickel's electron configuration due to the Aufbau principle, which states that electrons fill orbitals of lower energy first, and the 3d orbitals are lower in energy than the 4s orbital at this stage.
What is the final electron configuration for nickel, and how is it determined?
-The final electron configuration for nickel is [Ar] 3d⁸ 4s². It is determined by filling the orbitals in order of increasing energy, starting from the lowest.
What are valence electrons and why are they important in chemistry?
-Valence electrons are the electrons in the outermost shell of an atom. They are important in chemistry because they are the ones involved in chemical reactions and bonding.
How does the periodic table help in determining the electron configuration of elements like nickel?
-The periodic table helps in determining the electron configuration by showing the order in which elements fill their orbitals. Elements in the same group have similar electron configurations, which can be used to predict their chemical properties.
What is the significance of the d-block in the electron configuration of nickel?
-The d-block is significant in the electron configuration of nickel because it is the block where nickel fills its 3d orbitals with eight electrons, which is a key part of its electron configuration.
Outlines
🔬 Introduction to Nickel's Electron Configuration
The video begins by explaining how to determine the electron configuration for nickel, which has 28 electrons. The process involves filling the electron shells and orbitals in the correct order, starting from the lowest energy level to the highest. The periodic table is divided into s, p, and d blocks, and electrons are assigned to these blocks accordingly. The explanation includes the importance of understanding the periodic table for gaining intuition about element reactions.
🧮 Alternative Method for Electron Configuration
An alternative method for determining electron configuration is presented, which involves using a diagonal rule diagram to fill the electron shells. This method requires keeping track of the number of electrons filled in each shell and orbital. The process involves filling the s, p, and d orbitals in a specific order, and the example of nickel's electron configuration is used to illustrate the method. This method can be more complex and less intuitive than using the periodic table directly.
📚 Importance of Electron Configurations in Chemistry
The final section emphasizes the importance of learning electron configurations for understanding chemical reactions. Knowing which electrons are in the outermost shell (valence electrons) is crucial for predicting how elements will interact. The video notes that while electrons do not stay in fixed positions and can behave unpredictably, the configurations provide a useful framework for understanding their general behavior. The method helps in identifying the most reactive electrons, which are essential for studying chemistry.
Mindmap
Keywords
💡Electron Configuration
💡Orbitals
💡S-block, P-block, D-block
💡Valence Electrons
💡Atomic Number
💡Energy Shells
💡Subshells
💡Pauli Exclusion Principle
💡Aufbau Principle
💡Electron Configuration Notation
Highlights
Nickel has 28 electrons and is categorized as an s-block element.
Helium is an example of an element in the s-block when discussing orbitals.
The d-block and p-block are distinct from the s-block in terms of electron configuration.
Electrons fill the 1s orbital first, followed by 2s and 2p orbitals in nickel.
The electron configuration for nickel involves filling the 3s and 3p orbitals in the third shell.
Nickel's electron configuration continues with the 4s orbital in the fourth shell.
The d-block is filled with electrons in nickel, specifically the 3d orbitals.
The highest energy state electrons in nickel are in the 3d orbitals.
The valence electrons in nickel are crucial for understanding its chemical reactions.
Nickel's electron configuration can be determined by counting protons and assuming a neutral state.
Energy shells and subshells are filled in a specific order, starting with s, then p, and finally d.
The filling of the d-block involves subtracting one from the period to determine the correct orbital.
The electron configuration for nickel is 3d8 4s2, reflecting the order of filling orbitals.
Understanding electron configurations helps predict how elements will interact in chemical reactions.
Electrons in atoms are not static but interact and move between orbitals in unpredictable ways.
The method of filling electron orbitals provides a framework for understanding electron behavior in atoms.
Valence electrons are the outermost electrons and are key in determining chemical properties.
Transcripts
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