Why are some elements not stable?

Why some elements are radioactive (unstable). When the atoms of an element have extra neutrons or protons it creates extra energy in the nucleus and causes the atom to become unbalanced or unstable.

What makes an element more stable?

Atoms are at their most stable when their outermost energy level is either empty of electrons or filled with electrons. Two of these are in the lowest energy level, eight are in the second energy level and then one electron is in the third energy level.

Why are some elements more stable than others?

They have a stable number of electrons and do not need to react with other atoms. All other atoms have less stable electron numbers, so they react with each other and share electrons to be more stable.

Why do some elements have no stable isotopes?

In 2 additional cases (bismuth and protactinium), mononuclidic elements occur primordially which are not monoisotopic because the naturally occurring nuclide is radioactive, and thus the element has no stable isotopes at all. For an element to be monoisotopic, it must have one stable nuclide.

What is the most unstable element?

francium
While it occurs naturally in uranium minerals, there is probably less than an ounce of francium at any time in the total crust of the earth. It has the highest equivalent weight of any element, and is the most unstable of the first 101 elements of the periodic system. Thirty-three isotopes of francium are recognized.

What determines stability of an atom?

The two main factors that determine nuclear stability are the neutron/proton ratio and the total number of nucleons in the nucleus.

What is stability of an element?

Nuclide stability Proton number Z, also named the atomic number, determines the position of an element in the periodic table. The last element in the periodic table that has a stable isotope is lead (Z = 82), with stability (i.e. half-lives of the longest lived isotopes) generally decreasing in heavier elements.

Which elements have no stable isotopes?

Isotopes per element. Of the known chemical elements, 80 elements have at least one stable nuclide. These comprise the first 82 elements from hydrogen to lead, with the two exceptions, technetium (element 43) and promethium (element 61), that do not have any stable nuclides.

What is the difference between stable and unstable isotopes?

Stable isotopes are naturally occurring forms of elements that are non-radioactive. Unstable isotopes are atoms having unstable nuclei. Therefore, these elements undergo radioactivity. This is the main difference between stable and unstable isotopes.

What is a stable element?

In this definition, “stable” means a nuclide that has never been observed to decay against the natural background. Thus, these elements have half lives too long to be measured by any means, direct or indirect. Stable isotopes: 1 element (tin) has 10 stable isotopes. 26 elements have 1 single stable isotope.