What is the difference between radioactive decay and radioactivity?

I'm so confused about radioactivity and nuclear energy... Please help...?

• I understand that most heavy nuclides are radioactive, and that only radioactive molecules can undergo decay. Is that correct so far? So why is carbon-14 used for dating? Isn't the molecule too small to decay? Decay: When they emit alpha particles, or beta particles, are physical particles actually being emitted? Literally? I understand that a beta particle is a electron, so if a molecule undergoes beta decay, electrons are emitted? Is that possible? I thought electrons can't be separated from a molecule. Thanks.

• Answer:

  I understand that most heavy nuclides are radioactive, and that only radioactive molecules can undergo decay. Is that correct so far? All atoms have protons and neutrons in their nucleus. The most stable element is Iron. The most stable isotope of Iron has 26 protons and 30 neutrons in its nucleus. The isotope of Iron with 26 protons and 33 neutrons is unstable, so it emits a beta particle TO BECOME MORE STABLE. The result is an atom of Manganese with 25 protons and 34 neutrons. Let’s take a closer look at what just happened!! The nucleus of the Manganese atom has 1 more proton and 1 less neutron than the nucleus of the Iron atom. A neutron became a proton by emitting a beta particle. Let me be more precise!! A neutral particle which we call a neutron became a positive particle which we call a proton by emitting a beta particle. According to the rules of positive and negative numbers, there are only 2 ways that 0 can become +1. 0 + +1 = +1 or 0 - -1 = +1 No particle was added to the nucleus, a beta particle was subtracted from the nucleus!! So, the beta particle must have a negative charge. When scientists investigated the properties of the beta particle, they found the beta particle to be identical to an electron. So, a beta particle is an electron, which means a neutron is made of a proton and an electron. Does this mean that atoms have electrons in 2 places, in the nucleus and in the shells? NO The atom has protons and neutrons in the nucleus and all the electrons are in the shells, just like you always believed. When scientists investigate the properties of a neutron they do not see any evidence that is anything like proton or an electron. They did discover that a neutron has more mass than a proton, but they still had no clue that the neutron had a proton and an electron inside it. It was only after the neutron emitted the beta particle, that scientists discovered that a neutron consists of a proton and an electron. There are three naturally occuring isotopes, with C-12 and C-13 being stable, while C-14 is radioactive, decaying with a half-life of about 5730 years. The most common isotope of carbon is C-12, with 6 protons and 6 neutrons. C-14 has 6 protons and 8 neutrons. These 2 extra neutrons make the nucleus of C-14 unstable. UNSTABLE MEANS RADIOACTIVE!! Plants take in CO2 from the air to do the photosynthesis that produces C6H12O6. Some of the carbon atoms in the CO2 are C-14 atoms, so some of the carbon atoms in the C6H12O6 are C-14 atoms. So, when we eat plants, we take in some C-14. So, all living things, both plant and animal, have C-14 in them. Carbon 14 is unstable because it has one too many neutrons in its nucleus. The C-14 nucleus can’t just kick out 1 neutron; so the only option it has is to emit a beta particle from a neutron, which changes the neutron to a proton. Here is the equation for the radioactive decay of C-14 6 C 14 → 7N 14 + β- Now the nucleus has 7 protons and 7 neutrons. Looking at the periodic table, you will see that the element whose atoms have 7 protons and 7 neutrons in the nucleus is Nitrogen. N-14 is the most common isotope of nitrogen, because N-14 is the most stable isotope of nitrogen. Conclusion: The ratio of neutrons to protons determine the stability of a nucleus!! So why is carbon-14 used for dating? Isn't the molecule too small to decay? 1) C-14 is contained in all living things, old petrified trees and old bones. 2) ½ of the C-14 atoms have decayed to N-14 atoms in 5730 years. This half-life time is long enough to measure the age of 20,000 year old petrified trees. Some radioactive elements have a half-life of 3 seconds. If the half-life of C-14 was too short, all the C-14 would have become N-14 before we discovered the petrified tree trunk!! Decay: When they emit alpha particles, or beta particles, are physical particles actually being emitted? YES Uranium-227 emits an alpha particle and becomes Thorium-227 92 U 227 → 90 Th 223 + 2 He4 +1 Yes a Helium nucleus is emitted into the atmosphere where it attracts an electron and becomes a very, very stable atom of He. Literally? I understand that a beta particle is a electron, so if a molecule undergoes beta decay, electrons are emitted? Is that possible? I thought electrons can't be separated from a molecule. Here is the equation for the radioactive decay of C-14 6 C 14 → 7N 14 + β- This beta particle never was an electron orbiting the nucleus of the C-14 atom. I thought electrons can't be separated from a molecule. The atoms of many elements do not exist as atoms, because the atom is too unstable. A potassium atom has 1 electron its outer shell. The attraction between the positive nucleus of the potassium atom and this 1 electron is very weak. So, when this potassium atom collides with water molecule, the oxygen atom of the water molecules, which has a very strong attraction for 1 electron, will pull the electron off the potassium atom and form K+1 ion and FLAMMABLE HYDROGEN GAS. 2K + 2 HOH → 2 K+1 + 2 OH-1 + H2 + so much heat, that 2 H2 gas molecules instantly ignites and bonds to 1 O2 molecule from the air forming 2 H2O molecules. 2 H2 + O2 → 2 H2O