Beyond an element’s identity, its chemistry is governed by periodic properties such as how strongly it attracts electrons and how much energy it takes to ionise. This reference brings together four of the most-cited atomic properties for elements 1 to 54 in one place.
How it works
Type any element from hydrogen to xenon and the tool returns a property card with four measured quantities:
- Electronegativity on the Pauling scale, a dimensionless measure of electron-attracting power. Fluorine anchors the top of the scale at 3.98.
- First ionisation energy in kJ/mol, the energy to strip the outermost electron from a gaseous atom.
- Atomic radius in picometres (empirical radii).
- Melting and boiling points, shown in kelvin with a Celsius conversion.
These properties trend predictably across the table. Electronegativity and ionisation energy generally rise left-to-right across a period and fall down a group, while atomic radius does the opposite. Comparing two elements’ figures quickly tells you which will dominate the electron sharing in a bond.
Notes and examples
For a sodium-chlorine bond, chlorine’s electronegativity of 3.16 versus sodium’s 0.93 gives a difference of about 2.2 — large enough that the bond is ionic, which is why table salt is a crystalline solid rather than a molecular gas. Noble gases show a dash for electronegativity because they do not form ordinary chemical bonds. Temperatures are listed in kelvin first because several elements in this range, such as nitrogen and the noble gases, melt and boil far below 0 °C.