<span>The student is incorrect because helium has 2 valence electrons and it's in group 18 because the first energy level is full. Although helium is placed in Group 18 which generally has 8 valence electrons, it does not have 8 valence electrons as the student suggested. It was grouped together with the noble gases because it exhibits similar properties with them. </span>
Because in SI, the expectation is that area and volume will be expressed in terms of a linear dimension( the metre) or its multiples.
Answer:
When a substance gains or loses energy, its <u>temperature</u> or <u>state</u> changes. These two changes do <u>not</u> happen with respect to time; the temperature remains <u>the same</u> until the change of <u>state</u> is complete.
Explanation:
This statement is about energy and change of the state of the matter. By gaining or losing energy, the physical state of the matter can change into one another. Melting, freezing, condensation, evaporation, sublimation, and deposition are the processes that support to change the physical state of the matter. Change in state and change in the matter do not happen at the same time. A substance gains or loses energy to reach a specific temperature and remains constant until the physical change of matter is completed.
Answer:
Acid-base indicators are chemicals used to determine whether an aqueous solution is acidic, neutral, or alkaline. Because acidity and alkalinity relate to pH, they may also be known as pH indicators. Examples of acid-base indicators include litmus paper, phenolphthalein, and red cabbage juice.
Explanation:
The ionic compound will be soluble in water.
The value of the heat of solution of a substance is one of the factors that determine whether a substance will dissolve or not. A negative heat of solution signifies that the reaction will be spontaneous, so the ionic compound will dissolve in water.
