Answer:
A
Explanation:
eons are divided into eras and eras are based on major events and can vary in time so eons can vary in time
Explanation:
Metals react with oxygen to form basic oxides while they react with water to form alkaline solutions. Also, acidic oxides are oxides of nonmetals and they react with water to form acidic solutions.
Trends on the period table shows the variation of metallic character as you move across and down the periodic table. Metallic character of a element decreases across the period on the periodic table from left to right because atoms readily accept electrons in their outermost shell to form stable configurations. Metallic character increases as you move down the group in the periodic table and this is because electrons become easier to lose as the atomic radius increases (more outer shells are added), where there is decreasing attraction between the nucleus and the valence electrons.
So down the group, the acidity of oxide reaction with water decreases because the oxides are more basic down the group while across the period, the acidity of oxide increases because acidic oxides are formed as we move across the period.
Answer:
2 electrons
Explanation:
Oxygen has 6 valence electrons and to be stable it needs 8. That means it needs 2 more electrons to have a full octet.
Thus BeF2 is of most covalent character.
Anyways, covalent/ionic character is a bit tricky to figure out; we measure the difference in electronegativity of two elements bonding together and we use the following rule of thumb: if the charge is 0 (or a little more), the bond is non-polar covalent; if the charge is > 0 but < 2.0 (some references say 1.7), the bond is polar covalent; if the charge is > 2.0 then the bond is ionic. Covalent character refers to smaller electronegativity difference while ionic character refers to greater electronegativity difference.
Now, notice all of our bonds are with F, fluorine, which has the highest electronegativity of 3.98. This means that to determine character we need to consider the electronegativities of the other elements -- whichever has the greatest electronegativity has the least difference and most covalent character.
Na, sodium, has electronegativity of 0.93, so our difference is ~3 -- meaning our bond is ionic. Ca, calcium, has 1.00, leaving our difference to again be ~3 and therefore the bond is ionic. Be, beryllium, has 1.57 yielding a difference of ~2.5, meaning we're still dealing with ionic bond. Cs, cesium, has 0.79, meaning our difference is again ~3 and therefore again our compound is of ionic bond. Lastly, we have Sr, strontium, with an electronegativity of 0.95 and therefore again a difference of roughly 3 and an ionic bond.
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Explanation:
Matter also exhibits physical properties. Physical properties are used to observe and describe matter. Physical properties can be observed or measured without changing the composition of matter. These are properties such as mass, weight, volume, and density.
