Answer:
3 electrons
Explanation:
The elements of group 5A of the periodic table are the following:
nitrogen, sodium, arsenic, antimony and bismuth.
To determine the amount of electrons in the last energy level we need to know the electronic configuration of each element.
Electronic configuration
N: [He] 2s2 2p3
P: 1s2 2s2 2p6 3s2 3p3
As: [Ar] 3d10 4s2 4p3
Sb: [Kr] 4d10 5s2 5p3
Bi: [Xe] 4f14 5d10 6s2 6p3
As we can see they all have 3 electrons in their last energy level
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A molecule has an empirical formula of ch, and its molar mass is known to be 26 g/mol and the molecular formula is C₂H₂ ethyne
Molecular formula of compound is (CH)n and the given molar mass is 26g/mol
Molar mass of (CH)n, C=12=n(12+1)=13n
So 13n and n=2
=13×2=26 and given molar mass is also 26g/mol
So here two carbon and two hydrogen so molecular formula is C₂H₂ and name is ethyne
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Answer:
6moles of water
Explanation:
Given parameters:
Number of moles of oxygen = 3moles
Reaction equation:
2H₂ + O₂ → 2H₂O
Unknown:
Number of moles of water formed = ?
Solution:
To solve this problem;
compare the number of moles in the reaction.
1 mole of oxygen gas will produce 2 mole of water
3 moles of oxygen gas will produce 3 x 2 = 6moles of water.
Pure substances can or can not be chemically combined.
Pure substances can be either elements or compounds, but not mixture. Mixture are different substances mixing together without being chemically combined, such as air, which is a mixture of oxygen, carbon dioxide, water etc. Mixture can be separated by physical methods, like filtration or decantation.
Meanwhile, elements are the substances that cannot be further separated by any means. No matter physical or chemical methods. Examples of elements are oxygen, hydrogen, neon and all the other ones from the periodic table. Compounds are basically elements joining together, but they’re chemically combined which means their electrons (kind of subatomic particle) are either shared or given away. These elements can only be separated by chemical methods like electrolysis or heating.
Therefore, as long as the substance cannot be separated by physical methods, it can be considered as a pure substance. We can now conclude that pure substance can be (element) or can not be (compound) chemically combined.
The only food that provides all the nutrients that humans need is human milk," Hattner said. "Mother's milk is a complete food. We may add some solid foods to an infant's diet in the first year of life to provide more iron and other nutrients, but there is a little bit of everything in human milk.
