Elements

www.webelements.com
依個網站有齊你想要既資料,你只要係Periodic Table揀一個element,
例如Hydrogen,就可以知道以下資料:
Name: hydrogen
Symbol: H
Atomic number: 1
Atomic weight: 1.00794 (7) g m r
CAS Registry ID: 1333-74-0
Group number: 1
Group name: (none). While normally shown at the top of the Group 1 elements in the periodic table, the term "alkaline metal" refers only to Group 1 elements from lithium onwards.
Period number: 1
Block: s-block
Standard state: gas at 298 K (the lightest gas known)
Colour: colourless
Classification: Non-metallic
Availability:
Hydrogen is available commercially in pressurised tanks.
This sample is from The Elements Collection, an attractive and safely packaged collection of the 92 naturally occurring elements that is available for sale.
仲有佢既用途同特徵,有相同影片(e.g.group1elements既explosion)
你可以去一去個網站睇下有冇用~
希望幫到你^^

以下網站都很方便, 只要 click 個別元素名稱, 就有所須的資料.

英文網站：
- http://chemistry.about.com/library/blper5.htm 或
- http://en.wikipedia.org/wiki/Chemical_element 或
- http://en.wikipedia.org/wiki/Periodic_table
wikipedia 的內容有以下例子：
氫 http://en.wikipedia.org/wiki/Hydrogen
氧 http://en.wikipedia.org/wiki/Oxygen
碳 http://en.wikipedia.org/wiki/Carbon
鐵 http://en.wikipedia.org/wiki/Iron

中文網站：
- http://zh.wikipedia.org/w/index.php?title=%E5%85%83%E7%B4%A0%E5%91%A8%E6%9C%9F%E8%A1%A8&variant=zh-hk