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>
Answer:
n=17.85 moles
Explanation:
Given mass is, m = 1.5 kg = 1500 g
The molar mass of sodium bicarbonate is, M = 84.007 g/mol
We need to find the no of moles in 1.5 kg of Sodium bicarbonate . We know that, no of moles is equal to given mass divided by molar mass.
<h2>
So, there are 17.85 moles in 1.5 kg of Sodium bicarbonate.</h2>
Answer:
1) km 2) cm^ 3) no units (kg cancels) 4) g/cm^3 5) g 6) g°C
Explanation:
Like units will cancel ((m/km)*(km) = m
Non-cancelled units remain (ml)*(g/ml)*(°C) = g°C
Answer:
Cultivated rice paddies
Drilling of natural deposits
Fossil fuel use
Burning of biomass
Landfills
Explanation:
The bulk of the methane released into the atmosphere are as a result of various human activities.
- Cultivated rice paddies are a known source of methane
- The drilling of natural deposits and their exploration can release some methane into the atmosphere
- Burning of fossil fuel and biomass is a source of methane
- Landfills produces methane as organic materials begins to decay.
<span>c.
reactivity
this is a physical property depends on how reactive something is</span>
