He diagram shows an electron shell model of a sodium atom. A central purple circle labeled N a has 3 concentric rings around it. The inner ring has 2 small green spheres. The middle ring has 8 small green spheres. The outer ring has 1 small green sphere.

How would the model change as the atom forms bonds?

The third shell would have eight electrons after the atom gains seven electrons to fill the outermost shell.
The third shell would be empty so that the eight electrons in the second level would be outermost after the atom loses one electron.
The first and third shells would be empty so that the atom would have eight electrons in its remaining shell after the atom loses three electrons.
The first shell would have two electrons and the second shell would have six electrons after the atom loses three electrons.

there are no correct statementd on the list of choices you provided.

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia

305.7

explanation:

density =m/v

density =917/3.00

density = 305.

approximately = 305.7

in four significant figures