In which of the following is the number of electrons the ion contains given correctly

Chemistry

1 answer:

larisa [96]2 years ago

8 0

Answer:

B. K+ has 18 electrons

Explanation:

Ions are formed when atoms of element gain or loose electrons.
When an atom looses electrons it forms a positively charged ion and when an atom gains electrons it forms a negatively charged ion.
Metal atoms such as potassium, magnesium and aluminium looses outer most electrons to positively charged ions.
Potassium atom has 19 electrons, 19 protons, with an electronic configuration of 2 : 8 : 8 : 1. To form an ion, K looses an electron to form a positively charged potassium ion (K+) with 18 electrons and 19 protons and an electronic configuration of 2:8:8.

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Will the ph of a solution of nh4cn be >7, <7, or =7?

never [62]

PH of a solution will be higher than 7

Ammonium cyanide is a salt formed by hydrogen cyanide and ammonia. Ammonia is a weak base and hydrogen cyanide is a weak acid.
NH₄CN + H₂O ⇒ NH₃ + HCN

NH₄⁺ + H₂O -----> H₃O⁺ + NH₃

CN⁻ + H₂O -----> HCN + OH⁻

Although both compounds are weak electrolytes, NH₃ is somewhat stronger base than HCN is a strong acid, so the solution reacts alkaline. We can prove this using Ka and Kb values:

Ka(HCN) = 4.9 x × 10⁻¹⁰

Kb(NH₃) = 1.8 × 10⁻⁵
Kw= 1.0 × 10⁻¹⁴

Let's first calculate Ka for NH₄⁺:
Ka(NH₄⁺) x Kb(NH₃) = pKw

Ka(NH₄⁺) = Kw/Kb(NH₃) = 5.6 x 10⁻¹⁰

Then, Kb for CN⁻:

Kb(CN⁻) x Ka(HCN) = pKw

Kb(CN⁻) = Kw/Ka(HCN) = 2 x 10⁻⁵

From this, we can see that the acid constant NH4⁺ is much lower than the base constant of CN⁻, which will say that the solution of NH₄CN will react slightly alkaline because of the higher presence of hydroxyl ions in solution.

7 0

3 years ago

Some versions of the periodic table show hydrogen at the top of Group 1A(1) and at the top of Group 7A(17). What properties of h

lawyer [7]

Answer:Hydrogen is placed such because it exhibits some similar characteristics of both group1 and group VII elements.

Explanation:

The reason why hydrogen is similar to group 1 metals:

#It has same valence electron and inorder achieve octet state it can lose that electron and forms H+ ion

#It acts as a good reducing agent similar to group1 metals

#It can also halides

Similarity to halogens:

#hydrogen can also gain one electron to gain noble gas configuration. It can combine with other non metals to form molecules with covalent bonding.