Which metal has the lowerst melting point?

Options

A. Cs
B. Na
C. Hg
D. Sn

Answer

To determine which metal has the lowest melting point, we can analyze the electronic configurations and the nature of metal bonding for various metals. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand Metal Bonding
Metal bonding strength is related to the number of unpaired electrons in the valence shell of the metal. The more unpaired electrons there are, the stronger the metallic bonds, which typically leads to higher melting points.

**Hint:** Consider how the arrangement of electrons affects the bonding strength in metals.

### Step 2: Analyze Cesium (Cs)
Cesium has the electronic configuration of xenon 6s¹. It has one unpaired electron in its outermost shell, making it relatively unstable and resulting in weaker metallic bonding.

**Hint:** Look for the number of unpaired electrons in the outer shell of the metal.

### Step 3: Analyze Sodium (Na)
Sodium has the electronic configuration of neon 3s¹. Similar to cesium, it has one unpaired electron, which also indicates weaker metallic bonding.

**Hint:** Compare the unpaired electrons in different metals to see how they influence melting points.

### Step 4: Analyze Mercury (Hg)
Mercury has the electronic configuration of xenon 4f¹⁴ 5d¹⁰ 6s². In this case, the 5d and 6s orbitals are filled, meaning it has no unpaired electrons available for bonding. This results in weaker metallic bonding and a lower melting point.

**Hint:** Check if the electron orbitals are filled or partially filled to determine the availability of unpaired electrons.

### Step 5: Analyze Tin (Sn)
Tin has the electronic configuration of krypton 5s² 4d¹⁰ 5p². It has two unpaired electrons in the 5p orbital, which means it can form metallic bonds, but not as effectively as metals with more unpaired electrons.

**Hint:** Consider how the number of unpaired electrons affects the ability to form strong metallic bonds.

### Conclusion
Based on the analysis, mercury (Hg) has the lowest melting point among the metals discussed because it has a completely filled electron configuration and no unpaired electrons available for bonding.

**Final Answer:** Mercury (Hg) has the lowest melting point.