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yKpoI14uk [10]
3 years ago
7

3. Which of the following is not true for atoms? (4 points) They combine to form elements and molecules. They contain negatively

charged electrons. They are the building blocks of matter. They are made up of elements.
Chemistry
1 answer:
Taya2010 [7]3 years ago
7 0
<h3><u>Answer;</u></h3>

They are made up of elements.

<h3><u>Explanation;</u></h3>
  • An atom is the smallest particle of matter that still retains the property of the element.
  • Two or more atoms combine to form elements or compounds. Elements are formed by two or more similar atoms, while compounds are formed by two or more different elements.
  • Atoms are made up of subatomic particles; protons, electrons and neutrons. Electrons are negatively charged, protons are positively charged while neutrons have no charge.
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The ammonia molecule in the diagram has the observed bond orientation because ...
aivan3 [116]

Answer:

  • Nitrogen has four pairs of electrons: 3 bonds and 1 lone pair in the valence shell;
  • Electrons repel one another based on the VSEPR theory;
  • Nitrogen has a total of 7 protons (its atomic number is 7) in its nucleus.

Explanation:

The shape and the bond orientation of molecules and ions are both explained by the valences shell electron pair repulsion theory (VSEPR).

Ammonia, NH_3, is a molecule which contains three N-H bonds, as well as one lone pair on nitrogen. According to the VSEPR theory, molecules try to acquire a shape which would minimize the repulsion exhibited by the electron clouds present, that is, between the bonding (shared in a bond) and non-bonding (lone pair) electrons.

In VSEPR, our main step is to calculate the steric number, this is the sum of the number of bonds (ignoring the multiplicity of any bond) and the lone pairs on a central atom. In ammonia, we have 3 bonds and 1 lone pair, totaling to a steric number of 4. A steric number of 4 without any lone pairs on a central atom and just bonds would yield a tetrahedral shape with bond angles of 109.5^o.

Now, in this case, since we have a lone pair instead of a bond, it is repelling stronger decreasing the bond angles to about 107^o.

The greater the number of lone pairs, the lower the angle becomes.

To summarize:

  • Nitrogen has four pairs of electrons: 3 bonds and 1 lone pair in the valence shell;
  • Electrons repel one another based on the VSEPR theory;
  • Nitrogen has a total of 7 protons (its atomic number is 7) in its nucleus.
3 0
3 years ago
you rent a car in Germany with a gas mileage rating of 12.8km/L. What is its rating in miles per gallon?
Oksi-84 [34.3K]

so one liter is about 2. something gallons so at 12.8 km/l you would get about 30 mpg which is insane but yeah

4 0
3 years ago
Read 2 more answers
Which element would have the lowest electronegativity? (1 point)
irinina [24]

The element that will have the lowest electronegativity is an element with a small number of valence electrons and a large atomic radius.

Electronegativity of an element is the ability or power of that element in a molecule to attract electrons to its Valence electrons.  The following are the properties of electronegativity:

  • It increases across a period from left to right of the periodic table,
  • It decreases down the periodic table groups
  • Group 1 elements are the least (lowest) electronegative elements. These elements have the lowest valence electrons with a large atomic radius.
  • Group 7 elements are the most electronegative elements.

Atomic radius of elements increase down a group because of a progressive increase in the number of shells occupied by electrons which increases the size. But it decreases across a period because electrons are accommodated within the same shell leading to greater attraction by the protons in the nucleus.

Learn more about electronegativity of elements here:

brainly.com/question/20348681

6 0
3 years ago
1. Marisa determined the melting point of a substance to be 24.5C. Find the percent error of her measurement if the actual melti
USPshnik [31]

Answer:

\%\ Error = 21.5\%

Explanation:

Given

Measured = 24.5

Actual = 31.2

Required

Determine the percentage error

First, we need to determine the difference in the measurement

Difference = |Actual - Measured|

Difference = |31.2 - 24.5|

Difference = |6.7|

Difference = 6.7

The percentage error is calculated as thus:

\%\ Error = \frac{Difference * 100\%}{Actual}

\%\ Error = \frac{6.7 * 100\%}{31.2}

\%\ Error = \frac{670\%}{31.2}

\%\ Error = 21.4743589744\%

\%\ Error = 21.5\% <em>approximated</em>

6 0
3 years ago
What is the mass of 3.20x10^23 formula units of iron (III) oxide (Fe2O3)?
yaroslaw [1]

The mass of iron (III) oxide (Fe2O3) : 85.12 g

<h3>Further explanation</h3>

Given

3.20x10²³ formula units

Required

The mass

Solution

1 mole = 6.02.10²³ particles  

Can be formulated :

N = n x No

N = number of particles

n = mol

No = 6.02.10²³ = Avogadro's number

mol of Fe₂O₃ :

\tt n=\dfrac{3.2.10^{23}}{6.02.10^{23}}=0.532

mass of Fe₂O₃ (MW=160 g/mol)

\tt mass=mol\times MW=0.532\times 160=85.12~g

4 0
2 years ago
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