I think I it’s gonna be C.
Dimitri Mendeleev was the first to put elements together on a table. He knew there were elements missing but he noticed a trend in some of the elements known at the time. Sodium, Lithium and other alkali metals all have the same properties so he put them under the same column and created other columns with similar attributes (Halogens, Noble gases, Alkaline earth metals). Over the years, new elements were discovered and put into the rough outline that Mendeleev created.
I hope that is about what you wanted.
Answer:
1. Ions are either negatively or positively charged species in which the number of electrons and protons are not equal.
2. The chemical bond that arises due to the sharing of electrons is termed a covalent bond.
3. The positively charged ions are called cations, which comprise more protons than electrons.
4. An example of a polyatomic anion is the hydroxide anion.
5. The system of assigning an unambiguous name to a compound is called nomenclature.
Selective serotonin reuptake inhibitors (SSRIs) are drugs that are antidepressants. These blocks the reuptake of a neurotransmitter leading to increases in their activity in the synaptic cells.
<h3>What are neurotransmitters?</h3>
Neurotransmitters are defined as the signaling molecules that are secreted by the nerve cells and act as signal transporter between the neurons and the other cells of the body.
The SSRIs class of drugs affects this neurotransmitter and blocks the pathway to the presynaptic cell. This, in turn, affects synaptic communication by increasing the amount of those SSRIs in the body and acting as a stimulant to treat various diseases.
Therefore, the SSRIs block the neurotransmitter and result in their effects.
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Partial pressure of gas A is 1.31 atm and that of gas B is 0.44 atm.
The partial pressure of a gas in a mixture can be calculated as
Pi = Xi x P
Where Pi is the partial pressure; Xi is mole fraction and P is the total pressure of the mixture.
Therefore we have Pa = Xa x P and Pb = Xb x P
Let us find Xa and Xb
Χa = mol a/ total moles = 2.50/(2.50+0.85) = 2.50/3.35 = 0.746
Xb = mol b/total moles = 0.85/(2.50+0.85) = 0.85/3.35 = 0.254
Total pressure P is given as 1.75 atm
Pa = Xa x P = 0.746 x 1.75 = 1.31atm
Partial pressure of gas A is 1.31 atm
Pb = Xb x P = 0.254 x 1.75 = 0.44atm
Partial pressure of gas B is 0.44 atm.
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