Answer:
only columns
Explanation:
All atoms of elements present in same group or column having same number of valance electrons. Thus the elements in same group having same properties.
For example:
Consider the second group. It consist of alkaline earth metals. There are six elements in second group. Beryllium, magnesium, calcium, strontium, barium and radium.
All have two valance electrons.
Electronic configuration of Beryllium:
Be = [He] 2s²
Electronic configuration of magnesium.
Mg = [Ne] 3s²
Electronic configuration of calcium.
Ca = [Ar] 4s²
Electronic configuration of strontium.
Sr = [Kr] 5s²
Electronic configuration of barium.
Ba = [Xe] 6s²
Electronic configuration of radium.
Ra = [ Rn] 7s²
They are present in group two and have same number of valance electrons (two valance electrons) and show similar reactivity.
They react with oxygen and form oxide.
2Ba + O₂ → 2BaO
2Mg + O₂ → 2MgO
2Ca + O₂ → 2CaO
this oxide form hydroxide when react with water,
BaO + H₂O → Ba(OH)₂
MgO + H₂O → Mg(OH)₂
CaO + H₂O → Ca(OH)₂
With sulfur,
Mg + S → MgS
Ca + S → CaS
Ba + S → BaS
Answer:
1.48 × 10²⁴ atoms
Explanation:
Step 1: Calculate the moles of argon
Argon is a noble gas, whose molar mass is 39.95 g/mol. We will use this data to find the moles corresponding to 98.1 grams of argon.
Step 2: Calculate the atoms of argon
In order to calculate the number of atoms of argon in 2.46 moles of argon, we have to consider the Avogadro's number: there are 6.02 × 10²³ atoms of Ar in 1 mole of Ar.
Answer:
No, the experimental result is different from the theoretical value.
Explanation:
Based on the given information, the mass of beaker and watchglass plus alum hydrate is 102.218 grams, and the mass of beaker and watchglass is 101.286 grams. Therefore, the mass of alum hydrate is:
= 102.218 grams - 101.286 grams
= 0.932 grams
Now the mass of anhydrous compound is,
= 102.218 grams - 101.798 grams
= 0.42 grams
Thus, the mass of water present is,
= 0.932 grams - 0.42 grams
= 0.512 grams
The mass percent of water is,
= mass of water/Total mass of hydrate * 100
= 0.512 grams / 0.932 grams * 100
= 54.93 %
Hence, the experimental result in not similar to the theoretical result.
Answer:
5.68×10¯¹⁰ m
Explanation:
From the question given above, the following data were obtained:
Energy (E) = 3.50×10¯¹⁶ J
Wavelength (λ) =?
Energy (E) and wavelength (λ) are related according to the following formula:
E = hv/λ
Where
E => is the energy
h => is the Planck's constant
v => is the velocity of electromagnetic radiation
λ => is the wavelength of the radiation.
With the above formula, we can obtain the wavelength of the radiation as follow:
Energy (E) = 3.50×10¯¹⁶ J
Planck's constant (h) = 6.63×10¯³⁴ Js
Velocity (v) = 3×10⁸ m/s
Wavelength (λ) =?
E = hv/λ
3.50×10¯¹⁶ = 6.63×10¯³⁴ × 3×10⁸ / λ
3.50×10¯¹⁶ = 1.989×10¯²⁵/ λ
Cross multiply
3.50×10¯¹⁶ × λ = 1.989×10¯²⁵
Divide both side by 3.50×10¯¹⁶
λ = 1.989×10¯²⁵ / 3.50×10¯¹⁶
λ = 5.68×10¯¹⁰ m
Thus, the wavelength of the radiation is
5.68×10¯¹⁰ m
Answer:
A Petal B Stigma C Stamen
Explanation:
