Answer:
Their valence electrons/properties
Explanation:
Elements in the same group of the periodic table have the same amount of valence electrons, which determines how they bond with other elements in other groups. This also determines their properties such as their reactivity. Since Li, Na, and K are in the same group, they must have similar properties and the same amount of electrons in their outermost shell.
Answer:
Three half lives corresponds to (12)3 . So a 18 quantity of the original isotope is retained. And the percentage of quantity of a radioactive material that remains after 5 half-lives will be . ∴NN0×100=10032=3.125.
Answer:
F
Explanation:
When an atom lose or gain electrons ions are formed.
There are two types of ions. Cation and anion.
Cation:
Cations are formed when atom lose electrons. For example:
X → X⁺ + e⁻
Anion:
It is formed when an atom gain electrons. For example:
X + e⁻ → X⁻
Fluorine is present in group seventeen. It has seven valance electrons. It gain one electron to complete the octet and form anion with charge of -1.
Calcium is alkaline earth metal. It is present in group two it loses two valance electrons and form cation with charge of +2.
Neon is noble gas. It already have complete octet. It can not form ions. To remove the electrons from noble gases very high temperature is required.
Zinc is present in group 12. It usually form cation by losing its two valance electrons but it can also show oxidation state -2.
Mass percentage is one way of representing the concentration of an element in a compound or a component in a mixture. To calculate percent by mass, you need to determine two things: the mass of just the element, and the molar mass of the whole compound. We calculate as follows:
.10 g NaCl / g NaCl + Water = ( 10.0 g NaCl + x ) / (10.0 g + 255 g + x )
x = 18.33 g NaCl needed
Energy is absorbed to break bonds, and released when bonds are formed.
