Answer:
A mole is the amount of pure substance containing the same number of chemical units as there are atoms in exactly
12 grams of carbon-12 (i.e., 6.023 X 1023).
Explanation:
Realize that pH + pOH = 14
so, 9 + pOH = 14 -> pOH = 5
pOH = -log[OH-]
5 = -log[OH-]
plug it into a calculator and you get 1.0 x 10^-5
alternatively, use [OH-] = 10^-pOH to get the same answer
[OH-] = 1.0 x 10^-5
The answer is: lose electrons and form positive ions.
Most metals have strong metallic bond, because of strong electrostatic attractive force between valence electrons (metals usually have low ionization energy and lose electrons easy) and positively charged metal ions.
The ionization energy (Ei) is the minimum amount of energy required to remove the valence electron, when element lose electrons, oxidation number of element grows (oxidation process).
For example, magnesium has atomic number 12, which means it has 12 protons and 12 electrons. It lost two electrons to form magnesium cation (Mg²⁺) with stable electron configuration like closest noble gas neon (Ne) with 10 electrons.
Electron configuration of magnesium ion: ₁₂Mg²⁺ 1s² 2s² 2p⁶.
It showed that atoms can be divided into smaller parts.
It showed that all atoms contain electrons.
Explanation:
The experiment carried out by J.J Thomson on the gas discharge tube by passing electric current through a tube filled with many different gases provided a good insight into the structure of an atom.
This experiment led to the development of the plum pudding model of the atom.
- Cathode rays and it properties were discovered in this set up.
- It furnished the scientific community with evidences that atoms can be divided into smaller parts.
- Since atoms now contain some subatomic particles, they can be broken down in like manner into further bits.
- The cathode rays which were later termed electrons became a fundamental particles known for every atom.
learn more:
Rutherford's model of the atom brainly.com/question/1859083
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