Answer:
Arsenic.
Explanation:
Hello there!
In this case, since insecticides are substances that act as poisons to get rid of insects in order to prevent their presence and/or reproduction in houses, companies, crops and others, a substance that has been widely used is the metalloid arsenic due to its direct affection of the insect's body (movement, performance, cellular functions).
In addition, high levels of arsenic in food could cause arsenic poisoning in humans as well, that is why such practice must be properly performed and by using the correct security protocol.
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Answer:
German chemist G.E. Stahl
Explanation:
this theory was first articulated in 1697
V = f 入 (velocity = frequency x wavelength)
<span>If we have the speed ( for wave in vacuum </span><span>i.e. 3 x 10^8 m/s) </span>
<span>Then the frequency of x-ray is </span>
<span>(3 x 10^8) ÷(1.15 x 10^-10) = 2.61 x 10^18 </span>
<h3><u>Answer;</u></h3>
+2
<h3><u>Explanation</u>;</h3>
- The electron configuration ofthe atom is 1s2 2s2 2p6 3s2. Upon forming an ion, its new configuration is 1s2 2s2 2p6.
- The atom has lost two electrons to form an ion which is positively charged with a charge of +2.
- In the given electronic configuration of an atom, '3s' shell is the outermost shell in which two electrons are present. For the stable configuration, these two electrons will be lost easily from the outer shell and atom will carry (+2).
- The atom has 12 electrons, and looses 2 electrons to attain stable configuration forming a positively charged ion with 10 electrons.
