All categories

3 years ago

Describe how elements are laid out on the periodic table of elements.

Chemistry

2 answers:

defon3 years ago

8 0

Answer:

The chemical elements are arranged in order of increasing atomic number.

Explanation:

Hydrogen = 1

Helium = 2

Lithium = 3

ratelena [41]3 years ago

5 0

Answer:

Elements are organized first by their atomic number. The number on top of each element is the atomic number which identifies each element, and increases from there. It is also further organized by groups and periods. Groups are vertical columns, and elements of each group tend to share similar properties. For example, group 2A is the alkaline earth metals, these elements all tend to react with other elements similarily and share other properties as well because they tend to have the same number of valence electrons, with certain rules and exceptions particularly for the groups in the center of the periodic table Periods are the horizontal rows. The period number indicates the number of energy levels. So all the elements in period 4 have four energy levels.

You might be interested in

An HCl solution has a pH of 3.350. After some NaOH was

Romashka [77]

Answer:

4.47x10^-4M

Explanation:

8 0

3 years ago

The gases carbon dioxide, oxygen, and argon are mixed in a container. All gases have the same partial pressure, and the total pr

polet [3.4K]

The partial pressure of argon can be calculated simply by dividing the total pressure by 3. This gives an answer equivalent to 10893.33 Pa. The clue behind this is the statement "all gases have the same partial pressure". This follows Dalton's Law of Partial Pressures which states that the total pressure is equal to the sum of the individual partial pressures.

4 0

3 years ago

What is the predicted change in the boiling point of water when 1.50 g of

dezoksy [38]

Answer:

0.00735°C

Explanation:

By seeing the question, we can see the elevation in boiling point with addition of BaCl₂ in water

⠀

$\textsf {While} \: \sf {\Delta T_b} \: \textsf{expression is used} \\ \textsf {for elevation of boiling point}$

⠀

The elevation in boiling point is a phenomenon in which there is increase in boiling point in solution, when the particular type of solute is added to pure solvent.

⠀

$\sf \large \underline{The \: formula \: to \: be \: used \: in \: this \: question \: is} \\ \boxed{T_b = i \times K_b \times m}$

⠀

Where 'i' is van't hoff factor which represents the ratio of observed osmotic pressure and the value to be expected.

and 'i' is 3 (as given in the question)

⠀

'Kb' is molal boiling point constant. And it's value is 0.51°C/mol(given in question)

⠀

'm' represent the molality of solution. Molatity is no. of moles of solution present in 1kg of solution.

⠀

To find molality, we have to divide no. of moles of solute by weight of solution

⠀

While first we need to no. of moles

$\sf \implies no. \: of \: moles = \frac{weight \: of \: solute}{molar \: mass \: of \: solute} \\ \\ \implies \sf no. \: of \: moles = \frac{1.5}{208.23} \\ \\ \sf \implies no. \: of \: moles = 0.0072$

⠀

Now, we will find molality

⠀

$\sf \hookrightarrow molality = \frac{no.\: of \: moles}{weight \: of \: solution} \\ \\ \sf \hookrightarrow molality = \frac{0.072}{1.5} \\ \\ \sf \hookrightarrow molality = 0.048 \: mol {kg}^{ - 1}$

⠀

$\textsf{ \large{ \underline{Now substituting the required values}}}$

⠀

$\sf \longmapsto \Delta T_b = 3 \times 0.51 \times 0.0048 \\ \\ \\ \boxed{ \tt{ \longmapsto \Delta T_b =0.00735{ \degree}C}}$

⠀

Henceforth, the change in boiling point is 0.00735°C.

7 0

2 years ago

What is the amount in grams of EDTA needed to make 315.1 mL of a 0.05 M EDTA solution. The molar mass of EDTA is 374 g/mol

statuscvo [17]

Answer:

58.92 g EDTA

Explanation:

315.1 mL = .3151 L

M = Moles / Liter

.3151 L x 0.5 mol EDTA x 374 g EDTA = 58.92 g EDTA

1 L EDTA 1 mol EDTA

4 0

2 years ago

How many atoms are found in 3.45g of CO2?

USPshnik [31]

Answer: The number of carbon and oxygen atoms in the given amount of carbon dioxide is $4.72\times 10^{22}$ and $9.44\times 10^{22}$ respectively

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Given mass of carbon dioxide gas = 3.45 g

Molar mass of carbon dioxide gas = 44 g/mol

Putting values in above equation, we get:

$\text{Moles of carbon dioxide gas}=\frac{3.45g}{44g/mol}=0.0784mol$

1 mole of carbon dioxide gas contains 1 mole of carbon and 2 moles of oxygen atoms.

According to mole concept:

1 mole of a compound contains $6.022\time 10^{23}$ number of molecules

So, 0.0784 moles of carbon dioxide gas will contain $1\times 0.0784\times 6.022\times 10^{23}=4.72\times 10^{22}$ number of carbon atoms and $2\times 0.0784\times 6.022\times 10^{23}=9.44\times 10^{22}$ number of oxygen atoms

Hence, the number of carbon and oxygen atoms in the given amount of carbon dioxide is $4.72\times 10^{22}$ and $9.44\times 10^{22}$ respectively

3 0

4 years ago