1. Protons
The center of an atom is called the nucleus. This dense core contains protons and neutrons packed tightly together. Protons have a positive electrical charge. The number of protons in an atom determines what element it is - hydrogen has 1 proton, oxygen has 8, and gold has 79.
2. Neutrons
Neutrons are also found in the nucleus alongside protons. Neutrons have no charge at all, making them neutral particles. They add mass to the atom and help keep the nucleus stable.
3. Electrons
Orbiting around the nucleus are electrons, which are tiny particles with a negative charge. They move extremely fast in regions called electron shells or energy levels. The first shell can hold up to 2 electrons, the second shell up to 8, and so on. Unlike the heavy nucleus, electrons are incredibly lightweight - about 1/1836 the mass of a proton!
Atomic Balance
In a neutral atom, the number of protons equals the number of electrons, so the positive and negative charges balance out. When atoms gain or lose electrons, they become charged particles called ions.
Though incredibly small (about 0.1 nanometers across), atoms make up everything you can see, touch, and even yourself!
Fun fact: If you could stack 1 trillion protons on top of each other, the pile would only be about the size of a grain of salt! Yet despite their tiny size, the repulsive force between two protons that are 1 meter apart is strong enough to lift a weight of 10 million tons.
What is an atom?
The largest unit of matterA type of moleculeThe smallest unit of matter that keeps the properties of an elementA particle found only in liquidsWhat are the three main parts of an atom?
Protons, electrons, and ionsProtons, neutrons, and electronsNucleus, electrons, and shellsNucleus, protons, and chargesWhere are protons located in an atom?
In the electron shellsOrbiting the nucleusIn the nucleusBetween electron shellsWhat electrical charge do neutrons have?
Positive chargeNegative chargeNo chargeVariable chargeWhat determines which element an atom is?
The number of electronsThe number of protonsThe number of neutronsThe combined mass of all particlesWhere do electrons move in an atom?
Inside the nucleusIn electron shells or energy levelsIn a straight line around the nucleusThey don't move at allWhat is the approximate mass relationship between protons and electrons?
They have equal massElectrons are about half the mass of protonsProtons are about 1836 times heavier than electronsElectrons have no massWhat happens when atoms gain or lose electrons?
They become different elementsThey become ionsThey split apart completelyThey stop existing
