| Z | Elem | Known | Stable | Unstable | Pred. | Gap | Nuclear γ (keV) | f(γ) (Hz) | Kα₁ (keV) | f(Kα₁) (Hz) | Context |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 21 | Sc | 25 | 1 | 24 | 59 | 34 | 889.3 / 1120.5 | 2.15×10^20 / 2.71×10^20 | 4.090 | 9.89×10^17 | ⁴⁶Sc (activation tracer) + XRF |
| 22 | Ti | 26 | 5 | 21 | 62 | 36 | 1157.0 | 2.80×10^20 | 4.511 | 1.09×10^18 | ⁴⁴Ti (via ⁴⁴Sc γ) + XRF |
| 23 | V | 26 | 1 | 25 | 62 | 36 | 983.5 | 2.38×10^20 | 4.952 | 1.20×10^18 | ⁴⁸V (PET/activation) + XRF |
| 24 | Cr | 26 | 4 | 22 | 62 | 36 | 320.1 | 7.73×10^19 | 5.415 | 1.31×10^18 | ⁵¹Cr tracer + XRF |
| 25 | Mn | 26 | 1 | 25 | 62 | 36 | 834.8 | 2.02×10^20 | 5.899 | 1.43×10^18 | ⁵⁴Mn industrial + XRF |
| 26 | Fe | 28 | 4 | 24 | 66 | 38 | — | — | 6.404 | 1.55×10^18 | Fe Kα₁ (ubiquitous XRF) |
| 27 | Co | 29 | 1 | 28 | 69 | 40 | 1173.2 / 1332.5 | 2.84×10^20 / 3.22×10^20 | 6.930 | 1.68×10^18 | ⁶⁰Co γ pair + XRF |
| 28 | Ni | 31 | 5 | 26 | 74 | 43 | — | — | 7.478 | 1.81×10^18 | XRF Kα₁ |
| 29 | Cu | 29 | 2 | 27 | 69 | 40 | — | — | 8.048 | 1.95×10^18 | Cu Kα₁ (calibration) |
| 30 | Zn | 30 | 5 | 25 | 71 | 41 | 1115.5 | 2.70×10^20 | 8.638 | 2.09×10^18 | ⁶⁵Zn + XRF |
| 31 | Ga | 31 | 2 | 29 | 74 | 43 | 93.3 / 184.6 / 300.2 | 2.26×10^19 / 4.46×10^19 / 7.26×10^19 | 9.251 | 2.24×10^18 | ⁶⁷Ga SPECT + XRF |
| 32 | Ge | 32 | 5 | 27 | 76 | 44 | — | — | 9.886 | 2.39×10^18 | XRF Kα₁ |
| 33 | As | 33 | 1 | 32 | 78 | 45 | 559.1 / 595.9 | 1.35×10^20 / 1.44×10^20 | 10.543 | 2.55×10^18 | ⁷⁴As + XRF |
| 34 | Se | 30 | 6 | 24 | 71 | 41 | 136 / 265 / 279.5 | 3.29×10^19 / 6.40×10^19 / 6.76×10^19 | 11.222 | 2.72×10^18 | ⁷⁵Se + XRF |
| 35 | Br | 31 | 2 | 29 | 74 | 43 | 554.3 / 776.5 | 1.34×10^20 / 1.88×10^20 | 11.924 | 2.88×10^18 | ⁸²Br tracer + XRF |
| 36 | Kr | 32 | 6 | 26 | 76 | 44 | 514.0 | 1.24×10^20 | 12.648 | 3.06×10^18 | ⁸⁵Kr (noble gas) + XRF |
| 37 | Rb | 32 | 1 | 31 | 76 | 44 | 511 (annih.) | 1.24×10^20 | 13.395 | 3.24×10^18 | ⁸²Rb PET + XRF |
| 38 | Sr | 34 | 4 | 30 | 81 | 47 | 514.0 | 1.24×10^20 | 14.165 | 3.42×10^18 | ⁸⁵Sr + XRF |
| 39 | Y | 32 | 1 | 31 | 76 | 44 | 898.0 / 1836.0 | 2.17×10^20 / 4.44×10^20 | 14.958 | 3.62×10^18 | ⁸⁸Y calibration + XRF |
| 40 | Zr | 34 | 5 | 29 | 81 | 47 | 724.2 | 1.75×10^20 | 15.775 | 3.81×10^18 | ⁹⁵Zr fission prod. + XRF |
Key terms in plain language
Open a term for a concise explanation of language used on this page.
Broadband
A general term for always-on, high-speed Internet access. Broadband can be delivered over fiber, cable, DSL, fixed wireless, cellular, or satellite networks.
Cloud Computing
Computing resources—such as applications, servers, storage, or databases—delivered from remote infrastructure and scaled as requirements change.
Cybersecurity
The practices and controls used to protect identities, devices, networks, applications, and data from unauthorized access, disruption, or manipulation.
Identity and Access Management (IAM)
The systems and policies that determine who a user is, what resources they may access, and how that access is authenticated and reviewed.
API
An application programming interface is a defined way for software systems to exchange data or request functions from one another.
Artificial Intelligence (AI)
Software designed to perform tasks involving prediction, classification, generation, reasoning, or decision support. Business use still requires clear data, governance, security, and human accountability.