All categories

3 years ago

What is the quantum number set of the ground-state electron that is found in lithium (Li) but not in helium (He)?

1 answer:

3 0

The electron configuration of lithium atom is: $Li:[He]2s^1$

The number "2" is the value of the principal quantum number "n". Letter "s" is associated with the value of secondary quantum number "l" and it is equal to zero. The value of "m" (or magnetic quantum number) is zero too. The quantum number set for the highest energy electron will be (2, 0, 0, 1/2).

You might be interested in

Which of the following reactions is balanced?

77julia77 [94]

Answer:

B. CaCl₂ + H₂CO₃ → CaCO₃ + 2HC

Explanation:

A balanced reaction has the same number of atoms in the both sides of the reaction. In the options:

A. CaCl₂ + H₂CO₃ → 2CaCO₃ + HCI

In this reaction there is 1 Ca in reactants and 2 in products -<em>The reaction is unbalanced-</em>

<em />

There is 1 Ca is both sides, 2Cl, 2H, 1C and 3 Oxygens -<em>The reaction is balanced</em>

C. CaCl₂ + 2H₂CO₃ → CaCO₃ + HCI

There is 1 Ca in both sides but 2Cl in reactants and 1 in Cl -<em>The reaction is unbalanced-</em>

<em />

D. 2CaCl₂ + H₂CO₃ →CaCO₃ + HCI

There are 2 Ca in reactants and 1 in Ca -<em>The reaction is unbalanced-</em>

3 0

3 years ago

Most geologists think that the movement of Earth's plates is caused by

butalik [34]

Answer: C. Convection currents in the asthenosphere.

Explanation: Most geologists think that the movement of Earth's plates is caused by convection currents in the asthenosphere.

***If you found my answer helpful, please give me the brainliest, please give a nice rating, and the thanks ( heart icon :) ***

7 0

3 years ago

What is the molar mass of chcl3?

svetlana [45]

Approximately 119.4 g, you take the mass on the periodic table of each element and add the numbers up

7 0

3 years ago

Please help! Thanks :D

Digiron [165]

Species shown in bold are precipitates.

Ca(NO₃)₂ + 2 KOH → Ca(OH)₂ + 2 KNO₃
Ca(NO₃)₂ + Na₂C₂O₄ → CaC₂O₄ + 2 NaNO₃

Cu(NO₃)₂ + 2 KI → CuI₂ + 2 KI
Cu(NO₃)₂ + 2 KOH → Cu(OH)₂ + 2 KNO₃
Cu(NO₃)₂ + Na₂C₂O₄ → CuC₂O₄ + 2 NaNO₃

Ni(NO₃)₂ + 2 KOH → Ni(OH)₂ + 2 KNO₃
Ni(NO₃)₂ + Na₂C₂O₄ → NiC₂O₄ + 2 NaNO₃

Zn(NO₃)₂ + 2 KOH → Zn(OH)₂ + 2 KNO₃
Zn(NO₃)₂ + Na₂C₂O₄ → ZnC₂O₄ + 2 NaNO₃

A double replacement reaction takes place only if it reduces in the concentration of ions in the solution. For example, the reaction between Ca(NO₃)₂ and KOH produces Ca(OH)₂. Ca(OH)₂ barely dissolves. The reaction has removed Ca²⁺ and OH⁻ ions from the solution.

Some of the reactions lead to neither precipitates nor gases. They will not take place since they are not energetically favored.

Compare the first and last row:

Both Ca(NO₃)₂ and Zn(NO₃)₂ react with KOH. However, between the two precipitates formed, Ca(OH)₂ is more soluble than Zn(OH)₂.

As a result, add the same amount of KOH to two Ca(NO₃)₂ and Zn(NO₃)₂ of equal concentration. The solution that end up with more precipitate shall belong to Zn(NO₃)₂.

Compare the second and third row:

Cu(NO₃)₂ reacts with KI, but Ni(NO₃)₂ does not. Thus, add equal amount of KI to the two unknowns. The solution that forms precipitate shall belong to Cu(NO₃)₂.

8 0

3 years ago

Information gathered by a scientist about the toxicity of chemical X and chemical Y showed that they had individual safe limits

timofeeve [1]

Answer:

Synergism

Explanation:

This is an example of Synergism. Synergism is nothing but working out of two medicines together.

Examples of medical synergies are when doctors treat microbial heart infections with ampicillin and Gentamicin and when people with cancer undergo radiation and chemotherapy or more than one chemotherapy drug at a time.

6 0

3 years ago