periodictable.com

https://periodictable.com· First analyzed 07 May 2026· Updated 07 May 2026

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periodictable.com

Mobile

Sponsored

Hosting Provider

Wolfram Research, Inc

IP Address

140.177.33.21

Site Location

🇺🇸 United Statesvia ip

Server Location

🇺🇸 Mattoon, United States

ASN

AS11106

Organization

Wolfram Research, Inc

Server

Apache

Nameservers

wri-dns2.wolfram.com.wri-dns3.wolfram.com.

Performance

100

Core Web Vitals

Weight

First Contentful Paint

342 ms10%

Speed Index

445 ms10%

Largest Contentful Paint

—25%

Total Blocking Time

0.0 ms30%

Cumulative Layout Shift

0.00025%

402 KB

10 requests

0–49

50–89

90–100

Architecture Stack

Monolithic

⚙️ SSR

Infrastructure

Hosting

Wolfram Research, Inc

Technology Stack

2 Technologies Detected

Analytics

Google Analytics

Web Servers

Apache

SEO Analysis

D43/100

Meta Tags14/15

Content6/12

Headings0/8

Technical4/21

E-E-A-T0/7

Images2/7

Links5/5

URL5/5

Social0/5

Freshness0/4

Mobile4/4

Indexability3/3

periodictable.comperiodictable.com

The Photographic Periodic Table of the Elements

The definitive online periodic table reference site including technical data, and photographs and descriptions of thousands of samples of the chemical elements.

Title Length47 chars

Recommended: 50-60 chars (~283px / 580px)

Description Length160 chars

Recommended: 120-160 chars

Issues (2)

• Missing H1 tag — every page should have exactly one H1
• Missing viewport meta tag — page may not be mobile-friendly (Google uses mobile-first indexing)

13 issues found

Upgrade to view details

Local SEO

Local Search Readiness

0/100

Poor

15 2

This site doesn't appear to be a local business. Local SEO signals are optional for non-local websites.

Sponsored

AI & LLM Readiness

F22/100

Bot Access

20/25

Machine Read.

1/25

Schema Data

0/25

Citation

1/25

AI Bot Access

14/14 accessible

AI Search

OAI-SearchBot

PerplexityBot

Claude-SearchBot

Gemini-Deep-Research

DuckAssistBot

Training

GPTBot

ClaudeBot

Google-Extended

Meta-ExternalAgent

Bytespiderinfo

Amazonbot

Applebot-Extended

CCBotinfo

Fetch

ChatGPT-User

Machine Readability

llms.txt

llms-full.txt

Semantic HTML

Heading Hierarchy

Text ratio:1%

Words:73

Token eff.:Too Short

Structured Data

No Schema

Citation Readiness

Opening Summary

Descriptive Headings

Canonical URL

Open Graph0/3

Twitter Card0/3

Language Tag

Publish Date

Author Info

Lists

Tables

TL;DR / Summary

About Page Link

Recommendations (12)

AI readiness recommendation preview...

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Sponsored

Accessibility

WCAG 2.1 Compliance

Evaluates how accessible your website is for users with disabilities, based on WCAG 2.1 guidelines. Checks images, forms, keyboard navigation, ARIA roles, and color contrast.

48/100

Passed

Critical

Warnings

Images & Alt Text

10/20

Checks if images have descriptive alt text for screen readers and visually impaired users.

Semantic Structure

3/20

Evaluates proper use of HTML5 semantic elements (header, nav, main, footer) and heading hierarchy.

Forms & Inputs

10/15

Verifies form fields have labels, error messages are clear, and inputs are properly associated.

Color & Contrast

15/15

Tests text-to-background color contrast ratios against WCAG AA/AAA minimum requirements.

Keyboard & Focus

9/15

Ensures all interactive elements are reachable and operable via keyboard (tab, enter, escape).

ARIA & Roles

1/15

Checks correct use of WAI-ARIA attributes (roles, states, properties) for assistive technologies.

5 recommendations

•Accessibility recommendation preview...

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Carbon Footprint

SWDM v4 · Eco-Score

Carbon emissions estimated using the Sustainable Web Design Model v4 (SWDM v4). Factors in data center, network, and device energy across new and returning visitors. Grade thresholds based on HTTP Archive percentiles.

48/100

50 mg

CO₂e / view

402.2 KB

Page Weight

90%

Cleaner Than

New Visitor

57 mg

Returning (cached)

28 mg

Annual (10K/mo)

6.0 kg

Emission Segments

Data Center

11 mg

Network

12 mg

Device

27 mg

Resource Breakdown

Images

133.1 KB

CSS

235.2 KB

HTML

34.0 KB

Green Hosting Not Verified

Wolfram Research, Inc

4 recommendations

•Carbon footprint recommendation preview...

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Security Score

40%Critical

No SSL

No WAF

N/A

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HTTP Headers

Developer Console

accept-ranges

bytes

connection

Keep-Alive

content-length

34474

content-type

text/html; charset=UTF-8

date

Thu, 07 May 2026 20:06:29 GMT

etag

"86aa-5cc982e205a6b"

Good Warning Issue

Email Infrastructure

Custom Mail Server

Score

SPF

DKIM

DMARC

MX Records (2)

mx2.wolfram.com

mx1.wolfram.com

Domain Information

periodictable.com

Domain Age

28y 10m

Created

24.06.1997

Expires

23.06.2026

Last Updated

04.09.2022

Registrar

GoDaddy.com, LLC

DNSSEC

Not Enabled

Privacy & Compliance

Cookie Consent Banner

Mobile Compatibility

Viewport & Responsive Test

Tests how well your website works on mobile devices. Checks viewport configuration, responsive layout, touch targets, font readability, and simulates rendering across different screen sizes.

27/100

Not Mobile Friendly

Viewport Meta

The viewport meta tag tells mobile browsers how to scale the page. Without it, mobile devices render at desktop width.

Responsive Design

Uses CSS media queries or flexible layouts to adapt content to different screen sizes automatically.

Touch Icons

Apple touch icons and favicons displayed when users add the site to their home screen on mobile devices.

Readable Font Size

Base font size should be at least 16px on mobile to ensure text is readable without zooming.

Relative Units

Using em, rem, %, or vw instead of fixed px values allows content to scale properly across screen sizes.

No H-Scroll Risk

No elements wider than the viewport that would cause horizontal scrolling on mobile devices.

Tap Targets OK

Interactive elements (buttons, links) are at least 48x48px with enough spacing to prevent accidental taps.

No Fixed Widths

No elements with fixed pixel widths that could overflow on smaller screens and break the layout.

5 recommendations

•Mobile compatibility recommendation preview...

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Typography & Readability

Times New Roman

WCAG Fail

60/100

Readability

/30

21/30

16px · LH --

Hierarchy

/20

10/20

WCAG

/25

15/25

1:1 min contrast

Performance

/25

14/25

1 font

Heading Font

Times New Roman

Body Font

Times New Roman

Serif16px

Contrast Ratio

1:1

22 issues

Reading Comfort

Single Family

left aligned

✅ Excellent readability: 16px body text is ideal for all devices.

❌ Low contrast: 22 elements fail WCAG AA (min 1.0:1). Increase text/background contrast.

✅ Lean font stack: 1 font families keeps load times fast.

⚠️ Missing font-display: swap — users may see invisible text while fonts load (FOIT).

Buy on MyFontsFlesch 55

Color Palette

9 unique colors

12.43:1 AAA Dark

#000000

Background· 50.199999999999996%

#cac7bf

Secondary· 2.9%

#121816

Primary· 17.5%

Business & Marketing Stack

1 Tools Detected

Growing

Behavior Analytics

Google AnalyticsFree

User behavior and product analytics

Sponsored

Scripts & Styles

2 Resources

Scripts

Styles

Async

Defer

Top Script Sources

google.com(1)google-analytics.com(1)

Website Identity