Explanation:
Elements that belong to same group contains same number of valence electrons. Hence, they tend to show similar chemical properties.
When we move across a period then number of electrons get added to the same shell. As a result, there will be no increase in size of elements.
Also, metals are the elements that belong to group 1, 2 and d-block elements are also known as metals. Metallic character of elements decreases when we move left to right in a periodic table.
As most reactive metals are placed on the left side of periodic table.
Since, size of elements increases on moving down the group. So, an element is able to easily lose its valence electrons because of less force of attraction between its nucleus and valence electrons.
As a result, there will be increase in reactivity of metals on moving down the group.
Thus, we can conclude that given sentences are as follows.
- Elements in the same group have the same number of valence electrons.
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Elements in the same period have the same number of electron shells.
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Metallic elements become less reactive as you move left to right in a period.
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Metallic elements become more reactive as you move top to bottom in a group.
HUNDRED GRAMS too because of the law of conservation of mass. The law of conservation of mass states that mass is neither created nor destroyed. So both sides will have the same mass
The ML of 0.85 m NaOH required to titrate 25 ml of 0.72m hbr to the equivalence point is calculated as follows
calculate the moles of HBr used
moles = molarity x volume
25 x0.072/1000= 0.0018 moles
write the equation for reaction
NaOH + HBr = NaBr + H2O
from reacting equation the mole ratio between NaOH to HBr is 1:1 therefore the moles of NaOH = 0.0018 moles
volume = moles/molarity
0.0018/0.085 = 0.021 L in Ml = 0.021 x1000=21.18 Ml ofNaOH
Answer:
Knowing that boron has an atomic mass of 10,811 means that all boron isotopes on average weigh 10,811 u.
Explanation:
The atomic mass of an atom is the mass of the atom measured in u (unified atomic mass unit), although we can also express it as Da (Dalton's unit)
Atomic mass refers to the average mass that all isotopes of that element have.
When we speak of isotopes we are referring to the element itself but with a different number of neutrons, which makes it modify its mass number.
