Question

properties of the elements
*numbers are for educational purposes only and are not intended to be a reference source.
directions: answer all questions using the correct units if required.
1 what temperature does lithium melt at?
2 which substance has an atomic radius of 50 pm?
3 which two elements have the closest atomic mass?
4 which element has the lowest boiling point?
5 how many degrees separate the boiling points of carbon and lithium?
6 which is the largest atom?
7 what is the relationship between atomic number and atomic mass?

Explanation:

Step1: Find lithium's melting - point

Check the table for lithium's melting - point value. It is 181.7°C.

Step2: Find element with atomic radius of 50 pm

Scan the atomic radius row in the table. Oxygen has an atomic radius of 50 pm.

Step3: Compare atomic masses

Helium has an atomic mass of 4.0 and lithium has an atomic mass of 6.9. These two are closest among the given elements.

Step4: Identify element with lowest boiling - point

Compare the boiling - point values. Oxygen has the lowest boiling - point at - 297°C.

Step5: Calculate difference in boiling points

The boiling point of carbon is 4827°C and that of lithium is 1342°C. The difference is \(4827 - 1342=3485^{\circ}C\).

Step6: Determine largest atom

Lithium has the largest atomic radius (145 pm) among the given elements, so it is the largest atom.

Step7: Analyze relationship

As the atomic number increases, the atomic mass generally increases, but not in a strictly linear fashion. For example, helium has atomic number 2 and atomic mass 4.0, lithium has atomic number 3 and atomic mass 6.9, carbon has atomic number 6 and atomic mass 12.0.

Answer:

1. 181.7°C
2. Oxygen
3. Helium, Lithium
4. Oxygen
5. 3485°C
6. Lithium
7. As atomic number increases, atomic mass generally increases but not in a strictly linear fashion.