All atoms of the same element have the same number of? Protons in their atomic nuclei (i.e., the same atomic number, or Z). For example, all oxygen atoms have eight protons in their nucleus, so they all have an atomic number of 8. The term “isotope” describes atoms of the same element that contain different numbers of neutrons in their nuclei.
The number of protons in an atom’s nucleus determines which element it is. For example, all atoms with six protons in their nuclei are atoms of the element carbon. The number of neutrons in an atom’s nucleus has very little effect on what element it is; however, it does affect the atom’s mass. Atoms of the same element with different neutrons are called isotopes.
Atoms of different elements have different numbers of protons in their nuclei. For example, all atoms of carbon have six protons in their nucleus, while all hydrogen atoms have only one proton. The number of protons in an atom’s nucleus determines what element it is.
Atoms of the same element can have different numbers of neutrons in their nuclei. These are called isotopes. For example, Carbon-12 atoms have six protons and six neutrons in their nucleus, while Carbon-14 atoms have six protons and eight neutrons. The number of neutrons in an atom’s nucleus affects its mass but not its chemical properties.
The term “nuclide” is used to describe a particular isotope of an element. For example, carbon-12 and carbon-14 are nuclides of the element carbon. The number 12 refers to the fact that these atoms contain six protons and six neutrons in their nuclei, while the number 14 refers to the fact that these atoms contain six protons and eight neutrons.
When writing about nuclides, it is common to use the notation “A/Z” to refer to the element represented by the nuclide. In this notation, A refers to the mass number of the nuclide (the sum of the number of protons and neutrons in the nucleus), while Z refers to the element’s atomic number. For example, carbon-12 would be written as 12C, while carbon-14 would be written as 14C.
Isotopes can be either stable or unstable. Stable isotopes do not undergo radioactive decay, while unstable isotopes do undergo radioactive decay. The half-life of an isotope is the amount of time it takes for half of the isotope atoms to decay.
For example, carbon-14 has a half-life of 5,730 years. This means that if you start with a sample of 100 grams of carbon-14, after 5,730 years, you will be left with 50 grams of carbon-14. After another 5,730 years (11,460 years total), you will be left with 25 grams of carbon-14. This process will continue until all of the carbon-14 has decayed.
Unstable isotopes can be used to date materials such as rocks and fossils. This is because the half-lives of unstable isotopes are known, and so by measuring the amount of an isotope present in a sample, it is possible to calculate how long ago the sample was formed.
For example, if you measure the amount of carbon-14 present in a fossil, and you know that the half-life of carbon-14 is 5,730 years, you can calculate that the fossil is 11,460 years old (two half-lives). This method is called radiocarbon dating.
Isotopes can also be used for other purposes, such as medical diagnosis and treatment. For example, iodine-131 is used to treat thyroid cancer, while technetium-99m is used in medical imaging.
No, atoms are not all the same size. The size of an atom is determined by its electron shell, which is the outermost layer of electrons that surrounds the nucleus. The larger the atom, the more electrons it has in its shell. The size of an atom also affects its chemical properties. For example, smaller atoms are more reactive than larger atoms because they have a greater surface-area-to-volume ratio. This means that there are more places for chemical reactions on their surfaces.