Attention and concentration are closely linked. You have to pay attention to achieve real concentration. So attention always precedes concentration.
Concentration span, like attention span varies from one person to another. Habits on concentration play a part as well. If you are used to concentrating in a noisy environments then you may have trouble in paying attention in a quiet room.
Everyone can improve their ability to concentrate by spending a little time each day exercising their mind.
Try the following three exercises. Concentrate hard and try to play as quickly as possible. At the end, find out which one you found hardest and why.