Answer:
<u>Physical Properties</u>
1. Metals are shiny but most non - metals lack this property.
2. Metals are able to deform under compression (malleable) but most non - metals lack this property.
<u>Chemical Properties</u>
<u>1</u><u>.</u><u> </u><u>Metal</u><u>s</u><u> </u><u>are</u><u> </u><u>good</u><u> </u><u>conductors</u><u>of</u><u> </u><u>heat</u><u> </u><u>and</u><u> </u><u>electricity</u><u> </u><u>but</u><u> </u><u>most</u><u> </u><u>non</u><u> </u><u>-</u><u> </u><u>metals</u><u> </u><u>are</u><u> </u><u>insulators</u><u>.</u>
<u>2</u><u>.</u><u> </u><u>Metals</u><u>,</u><u> </u><u>when</u><u> </u><u>exposed</u><u> </u><u>to</u><u> </u><u>water</u><u> </u><u>atmospheric</u><u> </u><u>oxygen</u><u> </u><u>tend</u><u> </u><u>to</u><u> </u><u>rust</u><u> </u><u>but</u><u> </u><u>non</u><u> </u><u>-</u><u> </u><u>metals</u><u> </u><u>lack</u><u> </u><u>this</u><u> </u><u>chemical</u><u> </u><u>property</u>
The answer is A. A mole of Cu has the same number of atoms as a mole of He atoms
Answer:
2.11 x 10²⁴ molecules.
Explanation:
- <em>It is known that every 1.0 mole of a molecule contains Avogadro's number of molecules (NA = 6.022 x 10²³).</em>
<em><u>Using cross multiplication:</u></em>
1.0 mole of H₂O contains → 6.022 x 10²³ molecules.
3.5 mole of H₂O contains → ??? molecules.
∴ 3.5 mole of H₂O contain = (3.5 mol)(6.022 x 10²³) = 2.11 x 10²⁴ molecules.
The atomic mass of the magnesium is : 24.31⋅g.
<h3>What is isotopes?</h3>
Isotopes are members of a family of elements that all have the same number of protons and different numbers of neutrons. The number of protons in the nucleus determines the atomic number of an element on the periodic table.
Magnesium has three natural isotopes: ²⁴Mg, ²⁵Mg, and ²⁶Mg.
<h3>What is atomic mass ?</h3>
Atomic mass is the mass of an atom. The SI unit of mass is the kilogram, while atomic mass is often expressed in the non-SI unit dalton (synonymous with uniform atomic mass unit). 1 Da is defined as 1/12 the mass of a free carbon-12 atom at rest in the ground state.
Calculation :
The atomic mass is the weighted average of the individual isotopic masses:
(23.99×78.99%+24.99×10.00%+25.98×11.01%)⋅g=24.31⋅g
To know more atomic mass please click here : brainly.com/question/338808
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