Question

which group tends to form -1 ions?
group A.Ca Ga
group B.Li O
group C.Cl S
group D.Br As
group E.Ba Sr
group F.O S

Answer 1

To determine which group tends to form -1 ions, we need to identify the likely charge of the ions formed by the elements listed.

Ions with a -1 charge are typically formed by nonmetals, particularly those in Group 17 (the halogens), which include fluorine (F), chlorine (Cl), bromine (Br), and iodine (I).

Let’s analyze the groups you've provided:

- **Group A: Ca (Calcium) and Ga (Gallium)** - Calcium is a metal that typically forms +2 ions, and Gallium usually forms +3 ions.

- **Group B: Li (Lithium) and O (Oxygen)** - Lithium is a metal that forms +1 ions, and Oxygen typically forms -2 ions.

- **Group C: Cl (Chlorine) and S (Sulfur)** - Chlorine is known to form -1 ions, while Sulfur typically forms -2 ions or can form other charges.

- **Group D: Br (Bromine) and As (Arsenic)** - Bromine is also known to form -1 ions, while Arsenic can form +3 or +5 ions.

- **Group E: Ba (Barium) and Sr (Strontium)** - Both are metals and typically form +2 ions.

- **Group F: O (Oxygen) and S (Sulfur)** - As mentioned before, Oxygen forms -2 ions, and Sulfur can also form -2 ions.

From this analysis, **Group C (Cl and S)** and **Group D (Br and As)** contain elements that have the potential to form -1 ions, but **Group D** specifically has Bromine, which is a halogen and commonly forms -1 ions.

Therefore, the best answer for a group that tends to form -1 ions is:

**Group D: Br (Bromine) and As (Arsenic)**, because bromine is a halogen that typically forms -1 ions.