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:
B. The [H1+] >[OH1-] and the solution is acidic
Answer: fixed shape and volume
Explanation:
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Explanation:
(1) The nucleus is positive and the electron cloud is positive.
(2) The nucleus is positive and the electron cloud is negative.
(3) The nucleus is negative and the electron cloud is positive.
(4) The nucleus is negative and the electron cloud is negative
Answer:
Pressure, P = 67.57 atm
Explanation:
<u>Given the following data;</u>
- Volume = 0.245 L
- Number of moles = 0.467 moles
- Temperature = 159°C
- Ideal gas constant, R = 0.08206 L·atm/mol·K
<u>Conversion:</u>
We would convert the value of the temperature in Celsius to Kelvin.
T = 273 + °C
T = 273 + 159
T = 432 Kelvin
To find the pressure of the gas, we would use the ideal gas law;
PV = nRT
Where;
- P is the pressure.
- V is the volume.
- n is the number of moles of substance.
- R is the ideal gas constant.
- T is the temperature.
Making P the subject of formula, we have;
Substituting into the formula, we have;
<em>Pressure, P = 67.57 atm</em>
