<u>Answer:</u> The electronic configuration of gallium is written below and number of valence electrons is 3.
<u>Explanation:</u>
Electronic configuration is defined as the representation of electrons around the nucleus of an atom.
Number of electrons in an atom is determined by the atomic number of that atom.
Valence electrons are defined as the electrons present in the outermost shell of an atom.
We are given:
An element Gallium having atomic number as 31.
Number of electrons = 31
Electronic configuration of Gallium is: 
This element has 3 electrons in its outermost shell. So, the number of valence electrons is 3
Hence, the electronic configuration of gallium is written below and number of valence electrons is 3.
Because subatomic particles ARE what make up atoms.
Answer: caffeine is a compound.
Explanation:
1) As stated c<span>affeine contains hydrogen, carbon, nitrogen, and oxygen atoms in a fixed ratio.
2) The definition of compound is a pure substance formed by chemical bonding of two or more fifferent elements. That means a defined ratio of the elements in the compound, which conferes uniform and equal properties to every part of the compound.
Some examples of compounds are salt (NaCl), water (H2O), vinegard (CH3 COOH).
A mixture combines several elements or compounds, not bonded by chemical bonds but mixed in ratios which may vary.
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Explanation:
Since, some of the given sample is stuck inside and behind the pipet. Hence, there will occur a decrease in the percent of acetic acid.
This is because a decrease in concentration of the acid will also lead to a decrease in the amount of sample taken for the estimation. Since. lesser is the amount or concentration present lesser will be its analyte concentration.
For example, we took 10 mg of a pickel sample but 3 mg of the sample remain stuck in the pipet. This means we actually titrating a sample less than 10 mg.
Therefore, the analyte concentration in the pickel will also be less.
