Covalent bond a chemical bond formed by two electrons that are shared between two atoms
ionic bond<span> a chemical bond formed by the electrostatic attraction between ions</span>
metallic bond<span> a bond characteristic of metals in which mobile valence electrons are shared among positive nuclei in the metallic crystal</span>
In 1869 he published a table of the elements organized by increasing atomic mass.
Mendeleev is called the "father of the modern periodic table
stated that if the atomic weight of an element caused it to be placed in the wrong group, then the weight must be wrong. (He corrected the atomic masses of Be, In, and U)
was so confident in his table that he used it to predict the physical properties of three elements that were yet unknown.
After the discovery of these unknown elements between 1874 and 1885, and the fact that Mendeleev's predictions for Sc, Ga, and Ge were amazingly close to the actual values, his table was generally accepted.
However, in spite of Mendeleev's great achievement, problems arose when new elements were discovered and more accurate atomic weights determined.
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Answer:
<u>C) 4</u>
Explanation:
<u>The reaction</u> :
- C (s) + 2H₂ (g) ⇒ CH₄ (g)
12g 4g 16g
Hence, based on this we can say that : <u>2 moles of hydrogen gas are needed to produce 16g of methane.</u>
<u />
<u>For 32g of methane</u>
- Number of moles of H₂ = 32/16 × 2
- Number of moles of H₂ = <u>4</u>
Lower
Melting points of molecular solids are lower than melting points of ionic compounds
"cg" is centigram, which is one-hundredth of a gram.
I will first convert from g to cg (multiply by 100), then from mL to L (multiply by 1000).
