Answer:
The elements in the alkaline earth metals group; beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra), have two electrons in their outer electronic shell.
Explanation:
Answer:
B
Explanation:
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Answer:
The parts of an atom are<em><u> protons, electrons, and neutrons.</u></em>
A proton is positively charged and is located in the center or nucleus of the atom.
Electrons are negatively charged and are located in rings or orbits spinning around the nucleus.
The number of protons and electrons is always equal.
The six electrons in the outermost shell allow selenium to have a variety of valence numbers.
The valence of selenium depends on which compound it is in. Selenium is very similar to sulfur. It may have a valence of 6.
EXAMPLE:
selenium hexafluoride SeF6, selenium trioxide SeO3
May have 4;
example
selenium tetrafluoride SeF4, selenium dioxide SeO2
MAy have 2;
example
selenium difluoride SeF2, selenium dichloride SeCl2
and may have -2;
example
hydrogen selenide H2Se
Explanation:
Mass of one atom of water = Mass of 1 mole / Avogadro's number
Mass of one atom of water = 18g/mol / 6.022×10²³molecules
Mass of one atom of water = 2.989 × 10^-23 g
Mass of glucose = 180(one molecule)
Mass of 100 molecules of glucose = 180×100 =18000
