A radioactive element is an element which is subject to spontaneous degeneration of its nucleus followed by the emission of alpha, beta and gamma particles. All elements with atomic numbers greater than 83 are radioactive.
The given phrases that describe radioactive elements are-
They have a consistent number of particles
- the particles are alpha, beta and gamma particles.
They have a half-life that determines their rate of decay.
Explanation for other options:
Not all elements occur in nature. Radioactive decay rates may not be constant as the decay happens when a radioactive substance emits a particle. It is not possible to predict exactly when a given atom of a substance will emit a particular particle. When the radioactive element release energy and particles, it decays.
Atoms are the smallest unit of non-living things and CELLS are the smallest unit of living things.
Answer:
Beryllium family
English Transcript:
Beryllium is the lightest member of the alkaline earth metals family. These metals make up Group 2 (IIA) of the periodic table. They include beryllium, magnesium, calcium, strontium, barium, and radium. Elements in the same column of the periodic table have similar chemical properties.
Spanish (Español) Transcripción:
El berilio es el miembro más ligero de la familia de los metales alcalinotérreos. Estos metales forman el Grupo 2 (IIA) de la tabla periódica. Incluyen berilio, magnesio, calcio, estroncio, bario y radio. Los elementos de la misma columna de la tabla periódica tienen propiedades químicas similares.
Measure the amount of chemical used, measure the mass before and after
Muscle contraction that results in a change in joint angle is called <span>concentric contraction.
This contraction occurs when enough force that can overcome the resistance applied is developed by the muscle where this force developed is larger than the force of the resistance applied.</span>
