Which of the following atoms has an electric charge? a sodium atom with 11 protons, 11 electrons, and 12 neutrons
a calcium atom with 20 protons, 18 electrons, and 20 neutrons
a helium atom with 2 protons, 2 electrons, and 2 neutrons
an iron atom with 26 protons, 26 electrons, and 30 neutrons

During physical science, ms. greene challenged her students to produce an energy transformation. james and jill wrapped a 4-inch nail with a coil of fifty turns of wire. they connected one end of the coil to one terminal of a knife switch. they connected the other terminal of the knife switch to the battery. finally, they connected the end of the coil to the other terminal of the battery. james held the tip of a 1-inch nail near the flat end of the 4-inch nail. jill closed the knife switch quickly and then opened it. the 1-inch nail was pulled toward the 4-inch nail. what is the best explanation of why the nail moved? a) electrical energy was converted to mechanical energy in the 1-inch nail. b) the 4-inch nail became an electromagnet and the magnetic force attracted the 1-inch nail. c) the electric current in the 4-inch nail was converted to mechanical energy in the 1-inch nail. d) the 4-inch nail had a positive charge and the 1-inch nail had a negative charge. opposites attracted.

For those who need theses answers i just took the test and got everyone of them

What 2 properties are used to classify radiation