Use the periodic table to identify the element represented by each of the following electron configurations. [He]2s2: ?

Answers

Answer 1

Answer:

Answer:

Be. Beryllium

Explanation:

Related Questions

Select all that apply.The solvent is usually referred to as the component of a solution which is present: as one liter as the larger quantity as the liquid which dissolves a solid as the smaller quantity Please help !!
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Copper has a density of 8.920 g/cm3. What mass of copper will occupy 45cm3? What volume of copper will have a mass of 1.0 kg?

A 25.5 liter balloon holding 3.5 moles of carbon dioxide leaks. How many grams of carbon dioxide escaped before the container could be sealed if the new volume of the balloon is 15.4L?

Answers

Assumptions made:
1. Temperature and pressure is constant.
2. Ideal gas is involved.

The variables involved in this problem is the moles of the gas and the volume. We find their relationship from the ideal gas law. PV=nRT. With all other concept besides n and V is constant, Volume is directly proportional to the amount of gas inside the balloon. Solving this is as simple as ratio and proportion.

25.5L/3.5 moles = =15.4L/X moles
X= 2.11 moles.

Answer:

61 grams

Explanation:

If the number of moles of CO₂ in the balloon is given to be 3.5 moles, the mass of CO₂ in the balloon will be

number of moles = mass ÷ molar mass

Hence, mass = number of moles × molar mass

Molar mass of CO₂ is 44g. This is 44 because the atomic mass of carbon is 12 while that of oxygen is 16. Thus, 12 + (16 × 2) = 44 g

mass= 3.5 moles × 44g

mass = 154g (which is the initial mass)

When the mass of CO₂ in the 25.5 liter balloon is 154g, the mass of CO₂ in the balloon when the volume of CO₂ in the balloon is 15.4 liter will be X

To get X,

25.5 L ⇒ 154g

15.4 L ⇒ X

cross-multiply, and

X = (15.4 × 154) ÷ 25.5

X = 93.00 grams (which is the final mass)

93.00 grams of CO₂ was left in the balloon, hence the mass of CO₂ that escaped will be: initial mass minus final mass

= 154g - 93g

= 61g

The mass of CO₂ that escaped is 61 grams

The molarity of an aqueous solution of NaCl is defined as the(1) grams of NaCl per liter of water
(2) grams of NaCl per liter of solution
(3) moles of NaCl per liter of water
(4) moles of NaCl per liter of solution

Answers

Answer:

The correct option is (4)

Explanation:

Molarity (M) is generally defined as the number of moles of a solute per liter of the solution.

The formula for molarity (from the definition above) is

M = number of moles (n) ÷ volume (in liters or dm³)

The unit for molarity is mol/L or mol/dm³

From the above, it can be deduced that the molarity of an aqueous solution of common salt (NaCl) is the number of moles of NaCl per liter of the salt solution.

Molarity = number of moles / volume in liters solution

Answer (4)

hope this helps!

How many moles are in 1.9 x 10^25 molecules of carbon dioxide

Answers

1 mole ----------- 6.02x10²³ molecules
? moles --------- 1.9x10²⁵ molecules

moles = 1.9 x 10²⁵ * 1 / 6.02x10²³

= 1.9 x 10²⁵ / 6.02x10²³

= 31.561 moles

hope this helps!

A 250-mL aqueous solution contains 1.56 mc025-1.jpg 10–5 g of methanol and has a density of 1.03 g/mL. What is the concentration in ppm?A 6.1 X 10^-8 ppm
B 1.5 X 1-^-5 ppm
C 0.061 ppm
D 15 ppm

Answers

The right answer for the question that is being asked and shown above is that: "B 1.5 X 1-^-5 ppm." A 250-mL aqueous solution contains 1.56 mc025-1.jpg 10–5 g of methanol and has a density of 1.03 g/mL. The concentration in ppm is that 1.5 X 1-^-5 ppm

Answer: The correct option is C.

Explanation: ppm is used to measure the concentration of solute in a given volume of solution. ppm is basically parts per million.

Mathematically,

$ppm=\frac{\text{Mass of solute (in mg)}}{\text{Volume of solution (in L)}}$

We are given:

Mass of methanol = $1.56* 10^(-5)g=1.56* 10^(-2)mg$ (Conversion Factor : 1g = 1000mg)

Volume of solution = 250 mL = 0.250L (Conversion Factor : 1L = 1000mL)

Putting values in above equation, we get:

$ppm=(1.56* 10^(-2)mg)/(0.250L)$

Concentration of methanol = 0.062ppm

Hence, the correct option is C.

The ionization energy of an element is a. a measure of its mass
b. the energy required to remove an electron from the element in its gaseous state
c. the energy released by the element in forming an ionic bond
d. the energy released by the element upon receiving an additional electron
e. none of the above

Answers

The ionization energy is energy required to remove an electron from element in it's gaseous state.

What is ionization energy?

Ionization energy is defined as the minimum energy required to remove an electron from its valence shell of an isolated gaseous atom,positive ion or molecule.Ionization energy is positive for neutral atoms from which it can be concluded that ionization is an endothermic process.

Closer are the valence electrons to nucleus ,higher is the ionization energy.It is usually expressed in electron volts or joules.Ionization energy increases from left to right in a period as more energy is required to remove electrons with small atomic size.

Ionization energy decreases down the group as atomic size increases due to which electrons are easily lost from the valence shell.

Learn more about ionization energy ,here:

brainly.com/question/6842791

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The ionization energy or ionization potential is - the energy required to remove an electron from an element in its gaseous state.

Will rate 5 stars! Please help!

Answers

i have no idea.. im not in chemistry yet.. but i think the first one is D

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