Explanation:
The representative elements are in columns A1 - A7. In an 18 column table the map is as follows:
A1 = column 1, hydrogen + alkali metals have 1 valence
A2 = column 2, alkaline earth metals have 2 valence
A3 = column 13, Boron family have 3 valence
A4 = column 14, Carbon group have 4 valence
A5 = column 15, Nitrogen family have 5 valence
A6 = column 16, Oxygen column - chalcogens have 6 valence
A7 = column 17, Fluorine column - halogens have 7 valence
<u>The group number of the representative elements = the number of valence electrons.</u>
Answer:
A methane molecule is made from one carbon atom and four hydrogen atoms. Carbon has a mass of 12.011 u and hydrogen has a mass of 1.008 u. This means that the mass of one methane molecule is 12.011 u + (4 × 1.008u), or 16.043 u. This means that one mole of methane has a mass of 16.043 grams.
メタン分子は、1つの炭素原子と4つの水素原子から作られています。炭素の質量は12.011uで、水素の質量は1.008uです。これは、1つのメタン分子の質量が12.011 u +（4×1.008u）、つまり16.043uであることを意味します。これは、1モルのメタンの質量が16.043グラムであることを意味します。^>^
Answer: 4.32g
Explanation:
MM of H2 = 1 x 2 = 2g/mol
2g of H2 contains 6.02x10^23 atoms.
Therefore Xg of H2 will contain 1.3 x 1024 atoms i.e
Xg of H2 = (2 x 1.3 x 1024) / 6.02x10^23 = 4.32g
Answer: 3.97 moles HCl
Explanation: Solution:
2.39x10²⁴ atoms HCl x 1 mole HCl /
6.022x10²³ atoms HCl
= 3.97 moles HCl
