Aneutral beryllium atom has four protons and five neutrons. how many electrons does it have?

4.5 electron because you have to add the proton and the electron and then divide by two.

Four electrons

Explanation:

Neutrons are neutral (have no charge), while protons have a positive charge and electrons have a negative charge with the same magnitude as the proton's charge. For an atom to be neutral, the positive and negative charges must cancel, so the number of electrons must equal the number of protons.

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.

conduction is the transfer of thermal energy (heat in transfer) due to collisions between the molecules in the object. collisions between adjacent atoms and molecules transfer kinetic energy from the warmer to the cooler object. the objects must be in physical contact.