Answer:1:En química, el número másico o número de masa es la suma del número de protones y el número de neutrones del núcleo de un átomo. Se simboliza con la letra A (el uso de esta letra proviene de alemán Atomgewicht, que quiere decir peso atómico, aunque sean conceptos distintos que no deben confundirse).
2:
Matter is discontinuous, and it is made of tiny particles called atoms
Explanation:
Matter is not a continuous structure, but it consists of tiny particles called atoms.
An atom consists of three types of particles:
- Proton: the proton is in the nucleus of the atom. it has a positive electric charge of
(also called fundamental charge). Its mass is
.
- Neutron: the neutron is also in the nucleus of the atom, but it has no electric charge. Its mass is similar to the mass of the proton (slightly heavier). Neutrons and protons are held together in the nucleus through the strong nuclear force.
- Electron: electrons are found in a "cloud" outside the nucleus. Electron has negative electric charge equal to
. Its mass is much approximately 1800 times smaller than that of the proton, so it is considered as negligible.
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Answer:
Freezing and condensation
Explanation:
Because they are exothermic, they release energy