C) lithium; 3
Explanation:
Considering the chart describing the element. According to the chart, the element is lithium with an atomic number of 3.
- Atomic numbers are used on the periodic table to arrange elements in their proper place.
- Atomic number is the number of protons in an atom.
- This number is unique for every atom.
- From the described chart, we see that the atom described is Lithium.
- The atomic number of neon is 10, boron is 5.
- Unless otherwise stated or shown, it can be nitrogen 7.
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No, a compound is two elements that have been chemically combined to form something different. A mixture is two things that have been mixed together without creating a chemical change
Answer:
2. For any given isotope, the sum of the numbers of protons and neutrons in the nucleus is called the mass number.
3. in fact, electron mass is so small that it is not counted in an atom's mass
Explanation:
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Answer:</h3>
0.002 moles
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Explanation:</h3>
Concept tested: Molarity
We are given;
- Volume of HCl as 20 ml or 0.02 L
- Molarity of HCl solution as 0.10 M
We are required to calculate the number of moles of HCl
What is molarity?
- Molarity is the concentration of a solution in moles per liter
How is it calculated?
- It calculated by dividing number of moles by volume;
- Molarity = Number of moles ÷ Volume
To calculate the number of moles we rearrange the formula;
Moles = Molarity × Volume
In this case;
Moles of HCl = 0.10 M × 0.02 L
= 0.002 moles
Therefore, the number of moles of HCl is 0.002 moles