The standard International System of Units (SI) unit of mass is the kilogram(kg). The kilogram is 1000 grams (g), first defined in 1795 as one cubic decimeter of water at the melting point of ice.
Answer:
The Aufbau Principle simply helps us determine electron configuration of an atom by stating that in the ground state of an atom or ion, electrons fill subshells of the lowest available energy level, then they fill subshells of higher energy level. For example, the 1s subshell is filled before the 2s subshell is occupied. Now, when trying to figure out the electron configuration of a calcium, you need to know its atomic number to determine its amount of total electrons. Calcium has an atomic number of 20, which means it has 20 protons and 20 electrons. First remember that the "s" subshell only holds 2 electrons, the "p" subshell only hold 6 electrons, and the "d" subshell only holds up to 10 electrons. Using the Aufbau principle below, we can determine that the first two electrons will go in the 1s orbital. Since 1s can only hold two electrons the next 2 electrons go in the 2s orbital. The next six electrons will go in the 2p orbital. The p orbital can hold up to six electrons. We'll put six in the 2p orbital and then put the next two electrons in the 3s. Since the 3s is now full we'll move to the 3p where we'll place the next six electrons. We now go to the 4s orbital where we place the remaining two electrons. With this, the calcium electron configuration will be:

Hope that helps you understand!
Answer:
Hydochloric acid
HCl
Explanation:
The name of the compound that gives hydrogen ion and chloride ions in the solution state is Hydrochloric acid.
Hydrochloric acid is made up of one atom of hydrogen and 1 atom of chlorine. We can also say, it is made up of 1 mole of hydrogen and 1 mole of chlorine.
The formula of this compound is HCl;
In solution:
HCl
→ H⁺ + Cl⁻
the answer to this is chemical change
Answer:
- <u><em>0.80 mol Al</em></u>
Explanation:
<u>1) Word reaction:</u>
- Aluminum + ferrous oxide → aluminum oxide + iron
This is a single replacement reaction, in which aluminum, a more acitve metal than iron, replaces the iron in the ferrous oxide to form aluminum oxide and iron.
<u>2) Skeleton chemical equation:</u>
<u>3) Balanced chemical equation:</u>
Add the coeffcients to comply with the law of conservation of mass:
<u>4) Mole ratio of Al and FeO:</u>
<u>5) Set a proportion with the unkown and solve:</u>
- x / 1.2 mol FeO = 2 mol Al / 3 mol FeO
- x = 1.2 mol FeO × 2 mol Al / 3 mol FeO =<u> </u><u>0.80 mol Al ← answer</u>