Answer:
B. Negative ion with a radius larger than the radius of the atom
Explanation:
When a negative ion is formed, electrons are added to the atom. As electrons are added to the atom, the size of the electron cloud increases accordingly.
As a result of this, a negative ion is always larger than its corresponding atom. Hence, nitrogen ion must be larger than the nitrogen atom based on the facts stated above.
Answer:
a. The phenolphthalein acts as a color changing indicator to signal the endpoint of the reaction.
Explanation:
Phenolphthalein is an organic substance with chemical formula 
.
It is a substance commonly used in acid-base titrations to indicate the end point in the titration because phenolphthalein is colorless in acidic solutions but turns a purplish-pink color in basic solutions.
In this way it helps visually to notice when the final point of the titration has been reached.
Answer:
118
Explanation:
Of these 118 elements, 94 occur naturally on Earth. Six of these occur in extreme trace quantities: technetium, atomic number 43; promethium, number 61; astatine, number 85; francium, number 87; neptunium, number 93; and plutonium, number 94.
Answer:
H₂O
Explanation:
Based electronegativity, water H₂O will have the higher melting point from the given choices. The binding force between hydrogen and oxygen is greater than for the others.
- In group 6, oxygen has the highest electronegativity.
- It pulls the shared electron closer in the bond.
- The high electronegativity between hydrogen and oxygen causes the elevated melting point between the two species.
