help please

Which pair represents isotopes? A) 116Cd and 116Sn B) 235U and 238U C) 54Cr and 54Fe D) 238Np and 239Pu What is the volume of a 63.4g piece of metal with a density of 12.86g/cm3 ? A) 6.65cm3 B) 19.5cm3 C) 425cm3 D) 4.93cm3 Question 10 (1 point) Which statement regarding the nucleus of an atom is correct? A) The nucleus contains protons and electrons and has no charge. B) The nucleus contains protons and electrons and is positively charged. C) The nucleus contains protons and neutrons and has no charge. D) The nucleus contains protons and neutrons and is positively charged