Galileo disproved the Ptolemaic theory, sanctioned for centuries by the Church, which held the Earth to be the central and principal object in the universe, about which all celestial objects orbited.
The answer is (1) 24. There are 26 protons in nucleus of Fe atom. There is 26 electrons in Fe atom. Fe atom loses 2 electrons and change to Fe2+ ion. So there is 24 electrons in Fe2+ ion.
Matter is made of what molecules and atoms are made of
Answer:
C.it has a lower melting temperature
Explanation:
A good way to solve this problem may be to think about a simple ionic compound, such as salt, NaCl:
- NaCl easily disolves in water, so options A and B are true about ionic compounds.
- Salt powder does not conduct electricity, however a concentrated solution of salt in water does. Meaning that option D is true as well.
- NaCl has a melting point of 801 °C, not particularly a low value. Thus the correct option is C.
Answer:
The correct answer to the question is
d. the nucleus is decaying
Explanation:
A radioactive isotope are variations of of a chemical element with different molecular mass and an unstable nucleus that emit alpha, beta or gamma radiation. An isotope releasing an alpha particle during nuclear decay, releases two neutrons and two protons which make up the alpha particle. If an beta particle is released, then a negative charge equivalent to an electron is released from the nucleus during disintegration. Both forms of nuclear decay results in the release of Gamma radiation.
ome isotopes release an alpha particle during nuclear disintegration; an alpha particle consists of two protons and two neutrons (equivalent to the nucleus of an atom of helium). Others release a beta particle, which is an electron, or negatively charged nuclear particle. Beta particles originate in the nucleus, presumably by breakdown of a neutron into its proton-electron components. Gamma rays are released during both types of radioactive decay.
