What happens when an uncharged capacitor is placed in a single loop with a resistor and a battery?

The capacitor will charge

Explanation:

When the capacitor is connected to the circuit containing the battery and the resistor, charges (electrons) will start flowing through the circuit, pushed by the electromotive force produced by the battery. In particular:

- electrons will flow from the negative terminal of the battery to one plate of the capacitor

- electrons will flow from the other plate of the capacitor to the positive terminal fo the battery

(It's important to keep in mind that the electrons never cross the gap between the plates of the capacitor.)

Therefore, negative charge will accumulate on one plate of the capacitor and positive charge will accumulate on the other plate: and so, there will be an increasing potential difference across the plates of the capacitor. Due to this increasing potential difference, it will become more and more difficult for the battery to "push" electrons on the negative plate (and to remove them from the other plates), so the current in the circuit will keep decreasing.

The process stops when the potential difference across the gap of the capacitor is equal to the e.m.f. of the battery: at this point, there is no more current in the circuit, and the capacitor is said to be fully charged.