Answer:
The first energy level is closest to the nucleus. The second energy level is a little farther away than the first. ... The electrons in the energy level farthest from the nucleus are called valence electrons. Atoms in the same column (group) in the periodic table have the same number of valence electrons.
Explanation:
Answer:
b) coefficient
Explanation:
Refer to this example:
CH4 +2 O2 → CO2+ 2 H2O
2 is used as a coefficient in this chemical equation.
Precautionary measures are rules often followed when working in labs and/or with chemicals.
In chemistry, a precipitation reaction is a double replacement reaction. It involves two reactants and two products. It means that the cations and anions of the compounds interchange with one another to yield two products. But what makes precipitation reactions different is that when two liquid reactants are allowed to react together, a solid substance called precipitate is formed. The solid appears because it is insoluble to the other product in aqueous state.
Therefore, basing on the choices given, precipitation reactions apply to letters C and D.
Answer:
H⁺(aq) + OH⁻(aq) ⇒ H₂O(l)
Explanation:
Let's consider the molecular equation that occurs when aqueous solutions of hydrofluoric acid and potassium hydroxide are combined. This is a neutralization reaction.
HF(aq) + KOH(aq) ⇒ KF(aq) + H₂O(l)
The complete ionic equation includes all the ions and molecular species.
H⁺(aq) + F⁻(aq) + K⁺(aq) + OH⁻(aq) ⇒ K⁺(aq) + F⁻(aq) + H₂O(l)
The net ionic equation includes only the ions that participate in the reaction and the molecular species.
H⁺(aq) + OH⁻(aq) ⇒ H₂O(l)
