i really need the ansewer so whats the answer?

The two elements that do not have a second energy levels are Hydrogen (H) and Helium (He)

Energy levels are nothing but the 3-D spaces around the nucleus of an atom. The electrons revolve around the nucleus in their respective energy levels. Each energy levels can accommodate only a particular number of electrons.

For example, first energy level can accommodate only a maximum of 2 electrons whereas second energy level can accommodate 8 electrons.

Hydrogen has 1 electron and helium has 2 electrons around their respective nucleus. In both hydrogen and helium, electrons are accommodated in the first energy level.

Hence, the two elements that do not have a second energy levels are Hydrogen (H) and Helium (He)

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Both transition metals and alkali metals are good conductors of heat and electricity, react with water, and are easily oxidized.

The alkali metals are elements of group 1 which are lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr).  They are also known as the s-block elements because they have their outermost electron in an s-orbital.

The alkali metals are shiny, soft, highly reactive metals and readily lose their outermost electron to create cations with charge +1. They can tarnish rapidly in the air due to oxidation by atmospheric moisture and oxygen.

Transition elements or transition metals are elements that have partially filled d-orbitals. An element having a d-subshell that is partially filled with electrons or can form stable cations with an incompletely filled d orbital.

Any element present in the d-block of the modern periodic table which consists of groups 3 to 12, is considered to be a transition element. For example, the mercury in the +2 oxidation state, corresponds to an electronic configuration of (n-1)d¹⁰. Many paramagnetic compounds are formed by transition metals because they have unpaired electrons in the d orbital.

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Answer:3.381 X 10^(-11)

Explanation:

The formula for buoyant force is F = -Volume*density*gravitational acceleration. Convert volume and density to SI units and then apply them in the formula where gravitational acceleration is 9.8m/s^2. Done

not gon find it here cuh

Explanation:

The concentration of the acetic acid solution is approximately 0.0128 mol/L, given the information provided.

To determine the concentration of the acetic acid solution, we need to use the given enthalpy change and the heat evolved in the reaction.

The enthalpy change (ΔH) is given as 55.7 kJ/mol, which represents the heat released or absorbed per mole of acetic acid involved in the reaction.

The heat evolved in the reaction is given as 716.12 J. However, we need to convert it to kilojoules to match the unit of the enthalpy change. There are 1000 J in 1 kJ, so 716.12 J is equal to 0.71612 kJ.

Now, we can set up a proportion to find the concentration of the acetic acid solution. The heat evolved is directly proportional to the moles of acetic acid involved in the reaction, which is in turn proportional to the concentration of the solution.

Let's assume the concentration of the acetic acid solution is c mol/L.

The proportion can be set up as:

ΔH (kJ/mol) / Heat evolved (kJ) = 1 mol / c L

Substituting the values we have:

55.7 kJ/mol / 0.71612 kJ = 1 mol / c L

Simplifying:

c = 1 mol / (55.7 kJ/0.71612 kJ)

c ≈ 0.0128 mol/L

Therefore, the concentration of the acetic acid solution is approximately 0.0128 mol/L, given the information provided.

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Water is the most abundant substance in earth. Water is a compound because it made of a number of H₂O molecules. Water is a homogeneous compound.

Compounds are substances formed by chemical bonding of two or more elements. All the molecules in the compounds will be identical. For example CO₂ where one carbon and two oxygens covalently bond together to form the compound.

Each compound is made of a number of molecules. Thus molecules are the basic units of compounds like we say as for atoms for every substances.

There are different types of compounds based on the type of bond and number of atoms etc namely ionic compounds, covalent compounds, coordination compounds etc.

Water contains two hydrogen atoms and one oxygen thus forms one molecule of water. Similar kinds of molecules joins together to form the compound.

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Type of force would put the soccer ball in motion is unbalanced force.

Unbalanced force is  defined as when the net force acting on the object is not equal to zero. The unbalanced force brings an object in motion. while balanced force acting on any object does not change the state of rest or uniform motion. The soccer ball moves from one place to another because unbalanced forces are acting on the soccer ball. this means the resultant force acting on soccer ball is not equal to zero.

Thus, Type of force would put the soccer ball in motion is unbalanced force.

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Answer:

b) Unbalanced force

Explanation:

Unbalanced force is the type of force which puts the soccer ball in motion while kicking it. Hence, option (b) is the correct answer.

Answer:

Tc

Explanation:

You just have to follow the rows with the exponents. Just remember that when we get to d, the number in the front is a period lower. Hope this helps!

Answer:

1.25 moles(N) of NaOH are present in 1000 gm of water.

and 1000gm = 1L

Considering the definition of atomic mass, isotopes and atomic mass of an element,  the isotope with masses of 62.939598 amu and 64.927793 amu have percent abundances of 69.80% and 30.20% respectively.

The atomic mass (A) is obtained by adding the number of protons and neutrons in a given nucleus of a chemical element.

The same chemical element can have the same atomic numbers, but the number of neutrons is different. These atoms are called isotopes of the element.

The atomic mass of an element is the weighted average mass of its natural isotopes, taking into account the relative abundance of each of them.

In this case, you know:

The percent abundance can be calculated as:

62.939598 amu× (x%÷100%) + 64.927793 amu× [(100-x)%÷100%]= 63.54 amu

Solving:

62.939598 amu× x+ 64.927793 amu× (1-x)= 63.54 amu

62.939598 amu× x+ 64.927793 amu× 1- 64.927793 amu× x= 63.54 amu

62.939598 amu× x- 64.927793 amu× x= 63.54 amu - 64.927793 amu× 1

-1.988195 amu× x= -1.387793 amu

x= (-1.387793 amu)÷ (-1.988195 amu)

x= 0.6980= 69.80%

Then, (100-x)%= (100 -69.80)%= 30.2%

Finally, the isotope with mass of 62.939598 amu has a percent abundance of 69.80% and the isotope with mass of 64.927793 amu has a percent abundance of 30.20%.

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Answer:

91.12 gram

Explanation:

Number of moles of Ammonia = 5.36

Molecular Mass of Ammonia = 14 + 3 × 1 = 17 gram/mol

Mass = Number of moles × Molecular mass

Mass = 5.36 mol × 17 gram/mol = 91.12 gram

answer

1. Neon

2. Astatine

3. oxygen

4. Arsenic

5. Silicone

6. Aluminium

7. Calcium

8. Sodium

The entropy  is -3.65 and -0.049 J per kelvin per mole respectively are the entropy of an insulated tank.

Entropy is a measure of randomness in a system. It is a state function. It can be denoted by heat supplied for a reversible system per temperature.

The final pressure will be the partial pressure of each gas in the mixture.

a) Partial pressure of nitrogen = mole fraction of nitrogen x total pressure = (0.79 mol) × (1 + 1 bar)/(0.79 + 0.29 mol) = 1.46 bar

Partial pressure of oxygen = mole fraction of oxygen x total pressure = (0.29 mol) ×(1 + 1 bar)/(0.79 + 0.29 mol) = 0.54 bar

Therefore,

ΔS of nitrogen= -R ln1.46 = -0. 38R

∆S of oxygen= -R ln 0.54= -0. 61R

ΔSuniv=−(0.79mol/0.79+0.29mol)×0.38 R−(0.29mol/0.79+0.29mol)×0.61

R=−0.27 R−0.16

R=−0.44

R=−3.65JK−1mol−1

(b) Partial pressure of nitrogen = mole fraction of nitrogen x total pressure = (0.79 mol) × (2 + 1 bar)/(0.79 + 0.29 mol) = 2.19 bar

Partial pressure of oxygen = mole fraction of oxygen x total pressure = (0.29 mol) × (2 + 1 bar)/(0.79 + 0.29 mol) = 0.80 bar

ΔS of nitrogen gas=−Rln1.46=−0.09R

ΔSof sulphur oxide =−Rln0.54=0.22R

ΔSuniv=−(0.79mol/0.79+0.29mol)×0.09R+(0.29mol/0.79+0.29mol)×0.22

R=−0.066 R+0.060

R=−0.049JK−1mol−1

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