Study Guides/Chemistry/1 to 30 Elements With Symbols & Electronic Configuration
Study Guide · Chemistry

Elements 1 to 30: Symbols and Electronic Configuration

Knowing the first 30 elements of the periodic table, along with their symbols and electronic configurations, is fundamental for chemistry students. The electronic configuration describes how electrons are distributed in the atomic orbitals of an element.

Question (Click to Flip)

Why does Chromium have an anomalous electronic configuration?

Answer

Chromium has the configuration [Ar] 3d5 4s1 instead of [Ar] 3d4 4s2 because a half-filled d-orbital (d5) is more stable than a partially filled one. An electron shifts from the 4s orbital to the 3d orbital to achieve this stability.

Card 1 of 1 free previews

Key Facts

Chromium (24) and Copper (29) are exceptions to the Aufbau principle due to the stability of half-filled and fully-filled d-orbitals.

Noble gases (He, Ne, Ar) are often used in brackets to represent the core electrons.

Elements 21 to 30 belong to the 3d transition metal series.

1. Elements 1 to 10

  1. Hydrogen (H): $1s^1$
  2. Helium (He): $1s^2$
  3. Lithium (Li): $[He] 2s^1$
  4. Beryllium (Be): $[He] 2s^2$
  5. Boron (B): $[He] 2s^2 2p^1$
  6. Carbon (C): $[He] 2s^2 2p^2$
  7. Nitrogen (N): $[He] 2s^2 2p^3$
  8. Oxygen (O): $[He] 2s^2 2p^4$
  9. Fluorine (F): $[He] 2s^2 2p^5$
  10. Neon (Ne): $[He] 2s^2 2p^6$

2. Elements 11 to 20

  1. Sodium (Na): $[Ne] 3s^1$
  2. Magnesium (Mg): $[Ne] 3s^2$
  3. Aluminum (Al): $[Ne] 3s^2 3p^1$
  4. Silicon (Si): $[Ne] 3s^2 3p^2$
  5. Phosphorus (P): $[Ne] 3s^2 3p^3$
  6. Sulfur (S): $[Ne] 3s^2 3p^4$
  7. Chlorine (Cl): $[Ne] 3s^2 3p^5$
  8. Argon (Ar): $[Ne] 3s^2 3p^6$
  9. Potassium (K): $[Ar] 4s^1$
  10. Calcium (Ca): $[Ar] 4s^2$

3. Elements 21 to 30

  1. Scandium (Sc): $[Ar] 3d^1 4s^2$
  2. Titanium (Ti): $[Ar] 3d^2 4s^2$
  3. Vanadium (V): $[Ar] 3d^3 4s^2$
  4. Chromium (Cr): $[Ar] 3d^5 4s^1$ (Exception)
  5. Manganese (Mn): $[Ar] 3d^5 4s^2$
  6. Iron (Fe): $[Ar] 3d^6 4s^2$
  7. Cobalt (Co): $[Ar] 3d^7 4s^2$
  8. Nickel (Ni): $[Ar] 3d^8 4s^2$
  9. Copper (Cu): $[Ar] 3d^{10} 4s^1$ (Exception)
  10. Zinc (Zn): $[Ar] 3d^{10} 4s^2$

Questions and Answers

Why does Chromium have an anomalous electronic configuration?+

Chromium has the configuration [Ar] 3d5 4s1 instead of [Ar] 3d4 4s2 because a half-filled d-orbital (d5) is more stable than a partially filled one. An electron shifts from the 4s orbital to the 3d orbital to achieve this stability.

More in Chemistry

⚗️

What is the Bond Order of O2 (Oxygen Gas)?

Learn how to calculate the bond order of O2 (Oxygen molecule) using Molecular Orbital Theory. Understand why the bond order is 2 and why oxygen is paramagnetic.

⚗️

What is Brisk Effervescence in Chemistry?

Learn the meaning of brisk effervescence in chemistry. Understand why the rapid escape of gas bubbles occurs during chemical reactions, with examples.

⚗️

BrF₃ ⇌ Br₂ + F₂ — Bromine Trifluoride Auto-Ionization Explained

Bromine trifluoride (BrF₃) undergoes auto-ionization: 2BrF₃ ⇌ BrF₂⁺ + BrF₄⁻. It acts as both a Lewis acid and base. Learn BrF₃ structure, reactions with Br₂ and F₂, and uses.

⚗️

Bromoethane: Formula, Structure, and Uses

Learn about Bromoethane (Ethyl Bromide). Discover its chemical formula, structural representation, preparation, and uses in organic chemistry.

⚗️

Burette — Definition, Use, and Diagram

What is a burette in chemistry? Learn about its use in titration, how to read a burette diagram, and why it has a stopcock at the bottom.

Study Smarter with Shinyu.ai

Turn this guide into revision flashcards, a practice exam, or an AI-generated podcast — free, no signup required.