Question

First: Identify the element from clue 16 ---- Period 6, Group 1. hint number 55 (Name and Atomic number, please 2 points) Second: you must "cross a divide". When you land back on "solid ground" there is a silvery white metal with an average mass of 178.5 amu. From there --- add 7 protons! Identify the element and describe the final steps you used to solve this last clue! (4 points)

Answer 1

Let's tackle the clues step by step.

**First Clue: Identify the Element from Clue 16**
- Period 6, Group 1 corresponds to **Francium (Fr)**, which has an atomic number of **87**.

So for the first part, the answer is:
- **Element:** Francium
- **Atomic Number:** 87

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**Second Clue: "Cross a Divide" and Identify the Element**
- The phrase "cross a divide" suggests moving from one side of the periodic table to another or possibly moving between groups or periods.
- "Silvery white metal with an average mass of 178.5 amu": The element that fits this description is **Tantalum (Ta)**, which is found in Group 5, Period 6, and has an atomic mass near 178.5 amu.

Now, according to the clue, we need to "add 7 protons":
- Tantalum (Ta) has an atomic number of **73**.
- Adding 7 protons to Tantalum's atomic number gives us:
\( 73 + 7 = 80 \).

The element with atomic number 80 is **Selenium (Se)**.

**Final Steps**:
1. Identified the silvery white metal with an average mass of 178.5 amu to be Tantalum (Ta).
2. Noted its atomic number of 73.
3. Added 7 protons to get the new atomic number: \( 73 + 7 = 80 \).
4. The element with atomic number 80 is **Selenium (Se)**.

So for the second part, the answer is:
- **Element:** Selenium
- **Atomic Number:** 80