24. <span>Valence electrons are most loosely held by the atom and are involved in chemical reactions. Chemical reactions occur when valence electrons are shared between atoms. The number of valence electrons determines how these reactions take place and what kind of bonds they form.
25 </span><span>Sodium has one valence electron and chlorine has seven valence electrons. The Ione valence electron from sodium is lost and is transferred to the chlorine atom. The result is a sodium ion with a charge of 1+ and a chloride ion with a charge of 1-. The oppositely charged ions attract each other and the charges balance to make a compound that is electrically neutral.
26. </span><span>Ionic compounds have high melting points and high boiling points compared to molecular compounds. Ionic compounds that are dissolved in water or melted will conduct electricity. Molecular compounds do not conduct electricity in either case.
27. </span><span>A covalent bond is formed when two atoms share valence electrons. Neither atom loses electrons or takes electrons from the other. No charged particles form. In an ionic bond, one or more electrons are transferred from one atom to another. Atoms that lose electrons become positively charged ions, and atoms that gain electrons become negatively charged ions. These oppositely charged particles then attract each other.
28. </span><span>A metal crystal consists of positively charged metal ions embedded in a "sea" of loosely held valence electrons that can move around easily. Heat travels through materials as the increased motion of the particles in the hotter parts of the material is passed along to the particles in the cooler parts. In a metal, since particles are easily set in motion, heat is easily transferred or conducted. The same is true for the conduction of electricity. Electricity can flow when charged particles, such as electrons, are free to move. Since the electrons in a metal crystal can move freely among the atoms, electricity is easily conducted.</span>
Is it an atomic model? I'm not really sure
Answer:
2 .Sulphurous acid
Explanation:
Sulphur dioxide can dissolve in water to form Sulfurous acid(H2SO3). sulphurous acid is weackly dibasic acid. sulphur dioxide is a major component of acid rain since it mixes with vapour in the atmosphere reacting to produce H2So4 .
Answer:
Mar 29, 2015 · Their settlements are much more permanent and include houses, storage buildings, etc. They also need preservation methods and storage techniques, unlike the nomads. Sedentary Societies were first to be seen near waterways such as rivers.
Explanation:
