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Now let’s zoom in… deeper into matter. Imagine breaking something again and again… until you reach the smallest possible piece. That piece is the atom. But atoms are not solid balls. They have structure. At the center, there is a nucleus. This nucleus contains protons, which are positively charged, and neutrons, which have no charge. Around the nucleus, electrons move. But they don’t move randomly. Early scientists thought electrons moved in fixed circular paths, like planets around the