Hydrogen

DIATOMIC NONMETAL

Bohr Model: Electrons arranged in energy shells around the nucleus.

Hydrogen is a chemical element with chemical symbol H and atomic number 1. With an atomic weight of 1.00794 u, hydrogen is the lightest element on the periodic table. Its monatomic form (H) is the most abundant chemical substance in the Universe, constituting roughly 75% of all baryonic mass.

Next →Helium

Quick Facts

Atomic Number 1

Period 1

Group 1

Phase Gas

Appearance colorless gas

About Diatomic Nonmetals

Diatomic nonmetals naturally exist as molecules of two atoms (e.g., O₂, N₂). They are typically gases at room temperature.

History

Discovered By Henry Cavendish

Named By Antoine Lavoisier

Physical Properties

Atomic Mass 1.008

Density 0.08988 g/L

Molar Heat 28.836 J/(mol·K)

Phase Transition (Melting & Boiling Points)

Hydrogen melts at 13.99 K and boils at 20.271 K.

Atomic Properties

Electron Config 1s1

Electronegativity 2.2

Electron Affinity 72.769 kJ/mol

Ionization Energy 1312 kJ/mol

Orbital Filling Diagram

This diagram visualizes electron configuration according to the Aufbau principle and Hund's rule. Boxes represent orbitals (s, p, d, f), while arrows indicate electrons with spin up or down. Electrons fill lower energy levels first and occupy orbitals singly before pairing.

Emission Spectrum Emission spectrum of Hydrogen

Photograph

Source: Wikipedia

External Resources

Wikipedia PubChem Royal Society of Chemistry Periodic Videos (YouTube)

Study Guide

Atomic Number

The number of protons in the nucleus, which defines the element.

Atomic Mass

The average mass of an atom, including protons and neutrons.

Electronegativity

A measure of how strongly an atom attracts electrons in a bond.

Ionization Energy

The energy required to remove an electron from an atom.

Electron Config

The arrangement of electrons in the atom's energy shells.