Dmitri Mendeleev devised the first periodic table.
A mixture means to elements where mixed together but a compound means they have bonded to make a different chemical
Answer is: <span>3. they conduct electricity.
1) acids taste sour, bases taste bitter.
2) acid </span><span>would react with metals and produce hydrogen gas:
Ca(s) + 2HCl(aq) </span>→ CaCl₂(aq) + H₂(g).
3) Acids and bases give ions in water solutions, so <span>they conduct electricity.
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An Arrhenius base is a
substance that dissociates in water to form hydroxide ions (OH⁻<span>).
In this example lithium hydroxide is an Arrhenius base:</span>
LiOH(aq) → Li⁺(aq) + OH⁻(aq).
An Arrhenius acid is a
substance that dissociates in water to form hydrogen ions or protons (H⁺<span>).
For example hydrochloric acid: HCl(aq) → H</span>⁺(aq) + Cl⁻(aq).
4) red litmus turn blue whe base is drop on it and blue litmus turn red when acid is drop on it.
5) bases have pH greater than 7, acids have pH less than 7.
Answer is ₂₀⁴²Ca.<span>
In AZX notation
A<span> - Represents the </span>mass number of atom.
Mass number = number of
protons + number of neutrons.
<span> It is shown at
the </span>above of the left side<span> of the
atom.</span>
<span> Here it is </span>42.
<span> </span>Z - Represents the atomic number.<span>
Atomic number = number of protons.
</span><span>It is shown at the</span> bottom line of the left side of the atom.<span>
</span>Here it is 20.<span>
X - </span>Represents the symbol of the atom.<span>
<span> </span></span>Here</span> X is Ca.<span>
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31 protons 31 electrons and 39 nutrons
