Not all clumps of matter contain atoms, as one of the previous posters has said. However, the objects we commonly encounter do contain atoms. The answer to the question of why this is the case can be gleaned by working backwards to what atoms are composed of.
Atoms, as you may be aware are themselves composed of protons, neutrons and electrons. The protons and neutrons form the nucleus of an atom and the electrons move around the nucleus in orbits. The reason that the electrons orbit the nucleus is due to the fact that the nucleus has a positive charge due to the presence of positively charged protons and zero charged neutrons while the electrons are negatively charged. The positively charged nucleus therefore exerts an attractive force on the negatively charged electrons (called the electromagnetic force), thereby keeping the electrons in orbit. So, in essence, the reason why atoms form at all is because of the configuration attained by protons, neutrons and electrons.
The question now becomes, why protons and neutrons form the nucleus and why protons, neutrons and electrons have different charges.
Protons and neutrons form the nucleus because they are held together by yet another type of force (strong force). Protons and neutrons are themselves composed of even smaller particles called quarks, which bind together due to strong force to form the protons and neutrons.
So, the question now becomes why the electromagnetic and strong forces exist and why protons, neutrons and electrons have different charges.
Current physics is reasonably good at explaining why the electromagnetic and strong forces exist (the reasons are slightly detailed to explain in simple terms so I will skip them). However, the exact reason for various particles having different charges is not fully understood so far. The most commonly accepted current theory of physics (the Standard Model) does not explain why these particles have different charges. Alternate theories such as the Superstring theory do try to explain why particles have different charges (or different properties such as mass, etc. for that matter) but such theories are based only on approximate frameworks so far and cannot be fully tested today. Therefore, the exact answer to the question of charge is currently unclear.
Atoms, as you may be aware are themselves composed of protons, neutrons and electrons. The protons and neutrons form the nucleus of an atom and the electrons move around the nucleus in orbits. The reason that the electrons orbit the nucleus is due to the fact that the nucleus has a positive charge due to the presence of positively charged protons and zero charged neutrons while the electrons are negatively charged. The positively charged nucleus therefore exerts an attractive force on the negatively charged electrons (called the electromagnetic force), thereby keeping the electrons in orbit. So, in essence, the reason why atoms form at all is because of the configuration attained by protons, neutrons and electrons.
The question now becomes, why protons and neutrons form the nucleus and why protons, neutrons and electrons have different charges.
Protons and neutrons form the nucleus because they are held together by yet another type of force (strong force). Protons and neutrons are themselves composed of even smaller particles called quarks, which bind together due to strong force to form the protons and neutrons.
So, the question now becomes why the electromagnetic and strong forces exist and why protons, neutrons and electrons have different charges.
Current physics is reasonably good at explaining why the electromagnetic and strong forces exist (the reasons are slightly detailed to explain in simple terms so I will skip them). However, the exact reason for various particles having different charges is not fully understood so far. The most commonly accepted current theory of physics (the Standard Model) does not explain why these particles have different charges. Alternate theories such as the Superstring theory do try to explain why particles have different charges (or different properties such as mass, etc. for that matter) but such theories are based only on approximate frameworks so far and cannot be fully tested today. Therefore, the exact answer to the question of charge is currently unclear.