In a Covalent bond which statement is true

Will mark brainliest how many electrons can be held in the energy level n = 4?

Movement that is like a t a type of wave that transfers energy where the particles in the medium move in a circle motion while the energy travels left or right. a type of wave that transfers energy where the particles in the medium move perpendicular to the direction in which the energy is traveling. transfers energy from one location to another a type of wave that transfers energy where the particles in the medium move parallel to the direction in which the energy is traveling. movement that is back and forth, like an equal sign = 1. wave 2. parallel movement 3. perpendicular movement 4. transverse wave 5. longitudinal wave 6. surface wave

Which particles make up the nucleus of an atom? a. protons and electrons b. neutrons and electrons c. protons only d. protons and neutrons e. neutrons only