Chemistry Metal 問題

1.
The electrical conductivity of semi-conductor is low at room temperature. Its resistance is greater than metal conductor but lower than electrical insulator.

2.
Atoms of different elements have different numbers of protons and electrons.
In most cases, atoms of different elements have different numbers of neutrons. But in rare cases, atoms (isotopes) of different elements would have the same number of neutrons.
For example, All Na atoms have 11 protons and 11 electrons, and all Mg atoms have 12 protons and 12 electrons. They have different numbers of protons and electrons. However, The isotopes 23Na and 24Mg have the same number of neutrons (12 neutrons), although they have different numbers of protons and electrons.

3.
Copper has two isotopes, 63Cu and 65Cu. A piece of copper wire is made up of about 70% of the 63Cu atoms (29p 29e 34n) and about 30% of 65Cu atoms (29p 29e 36n). 63Cu atom and 65Cu atom have 34 and 36 neutrons respectively.