The elements that have the same valence are, mainly, in the same principal groups (principal columns) of the periodic table.
The principal columns are 1, 2, 13, 14, 15, 16, 17 and 18.
For example:
1) the elements with valence 1+ are in the first column:H, Li, Na, K, Rb, Cs, Fr.
2) The elements with valence 2+ are in the second column: Be, Mg, Ca, Sr, Ba, Ra.
3) The elements with valence 2- are in the column 16: O, S, Se, Te, Pb
But also those elements may have other valences: S, Se and Te, have also valences 2, 4 and 6. And Pb have valences 2 and 4.
4) The elements with valences 1-, 1, 3, 5 and 7 are in the column 17: Cl, Br, I, At.
F, the first element of group 16, has valence 1- and 1+
Hello!
SOLID- atoms are packed tightly together with little movement. Has a definite shape and volume.
LIQUID- atoms are packed loosely together with some movement. Has a definite volume but NO definite shape.
GAS- atoms are spread out with lots of movement. Has NO definite shape or volume.
ICE- when a liquid turns into a solid (freezing).
WATER- when a solid turns into a liquid (heat is added)
WATER VAPOR- when a liquid turns into a gas (boiling)
Hope this helped!
The rate of a chemical reaction depends on several factors which include:
1) Concentration of the reactants
2) Pressure (in case of gases)
3) Temperature
4) Catalyst
As molecules approach each other, they collide forming a transition state which then unravels to form the product. As the temperature is lowered the frequency of molecular collisions gets reduced which causes the reaction to slow down.
Ans C) Lowering the temperature
Answer:
The answer is A) -604KJ
Explanation:
I just took the Penn Foster test. =D you welcome!
Answer:
Filtration separates solids of different sizes.
Distillation takes advantage of differences in boiling points.
Evaporation removes a liquid from a solution to leave a solid material.
