Answer: The elements with properties intermediate between those of metals and nonmetals are called semimetals (or metalloids).
Answer:

Explanation:
<u>According to Arrhenius concept of acid and base:</u>
"When a base in a solution, produces/yields OH- (Hydroxide) ions."
So, when a base is dissolved in a solution, it produces OH- ions.
<u>For example:</u>
NaOH ⇄ Na⁺ + OH⁻ (So, it is a base)
![\rule[225]{225}{2}](https://tex.z-dn.net/?f=%5Crule%5B225%5D%7B225%7D%7B2%7D)
Hope this helped!
<h3>~AH1807</h3>
Answer:
<em>Butane has only two isomers and pentane has just three, but some hydrocarbons have many more isomers than these. As you increase the number of carbon atoms in a hydrocarbon, the number of isomers quickly increases.</em>
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Answer:
The United States took first steps to keep the air clean.
Explanation:
The US environmental protection agency was created in the year 1970 so this option is wrong.
November 15, 1990 however was a milestone in keeping the air clean, the signing f the amendments, the amendments set the stage for protecting the ozone layer, improving air quality and visibility.
The correct option is option A; The United States took first steps to keep the air clean.