미해결 질문How many protons, neutrons, and electrons are there in a neutral atom of 131I (iodine-131)?1542views
미해결 질문How many protons, neutrons, and electrons are there in a neutral atom of 30P (phosphorus-30)?1034views
미해결 질문An isotope of yttrium has 39 protons and 59 neutrons. What is the mass number of that isotope?2121views
미해결 질문The superscript preceding each hydrogen atomic symbol (H) represents which of the following?971views