Answer:
The number of energy levels increases as you move down a group as the number of electrons increases. Each subsequent energy level is further from the nucleus than the last. Therefore, the atomic radius increases as the group and energy levels increase. 2) As you move across a period, atomic radius decreases.
Explanation:
Which properties do not change the composition of a substance?
neither chemical nor physical properties
physical properties
chemical properties
chemical and physical properties
Answer:
Physical Properties
Explanation:
PHYSICAL PROPERTY
Answer:
phycical propertys
Explanation:
jut took the test got it right
2. Using the following data, calculate the average atomic mass of magnesium (give your answer to the nearest
.01 ) : Show all work!
Isotope: Mg Percent abundance: 78.70%
24
Isotope: 'Mg Percent abundance: 10.13%
25
Isotope:
Mg Percent abundance: 11.17%
26
Answer:
24.32
Explanation:
From the question given above, the following data were obtained:
Isotope A:
Mass of A = 24
Abundance (A%) = 78.70%
Isotope B
Mass of B = 25
Abundance (B%) = 10.13%
Isotope C:
Mass of C = 26
Abundance (C%) = 11.17%
Average atomic mass of Mg =..?
The average atomic mass of Mg can be obtained as illustrated below:
Average atomic mass = [(Mass of A × A%)/100] + [(Mass of B × B%)/100] + [(Mass of C × C%)/100]
Average atomic mass = [(24 × 78.70)/100] + [(25 × 10.13)/100] + [(26 × 11.17)/100]
= 18.888 + 2.5325 + 2.9042
= 24.3247 ≈ 24.32
Therefore, the average atomic mass of magnesium (Mg) is 24.32
What is the first step when using a microscope?
A. Place the microscope slide on the stage
B. Plug the microscope in and turn it on
C. Switch to the low power objective lens
D. Secure the slide to the stage clips
Answer:
I think the answer is B :)
Answer:
the first step is B
Explanation: I'm on this lesson
WHAT IS A NEWTON!! specifically the definition!!!!
Answer:
Explanation:
the SI unit of force. It is equal to the force that would give a mass of one kilogram an acceleration of one meter per second per second, and is equivalent to 100,000 dynes.
A sample contains 110.68 g of calcium. How many moles is this?
(1 mole Ca = 40.08 g)
Round to the nearest tenth and do NOT include a unit. (.e. 2.9)
Helppppp
Answer:
About 2.8
Explanation:
Which among the given combinations below represent a set of isotopes?
1.40 protons and 40 neutrons
II. 41 protons and 39 neutrons
3.42 neutrons and 48 protons
4 40 protons and 42 neutrons
V. 41 protons and 40 neutrons
A. I, II, III
B. III, IV
C.1, IV and II, V
D. 1, V and II. V
E.1. V
Look for the ones with the same number of protons and different neutrons number
Which pair of elements are most likely to form a molecular compound?
Nitrogen and Hydrogen
Calcium and Copper
Chlorine and Neon
Please help! I will mark brainliest if correct!
Answer: Two nonmetals.
Explanation:
Answer:The only pair of nonmetals is sulfur and fluorine.
Explanation:The pair of elements most likely to form a molecular compound with each other are two nonmetals.
If a feather and in Marble are dropped at the same time from the same height explain. Which object would hit the floor first based on air resistance?
Answer:
the marble would hit the floor first because the feather would be effected by air resistance
When ignited, a uranium compound burns with a green flame. The wavelength of the light given off by this flame is greater than that of _____.
Answer:
Ultraviolet light.
Explanation:
Uranium is a natural radioactive chemical element with the chemical symbol "U" and an atomic number of 92. Uranium is used for generating nuclear fuels which are typically used in powering atomic bombs and nuclear reactors in the field of electricity generation.
When ignited, a uranium compound burns with a green flame. The wavelength of the light given off by this flame is greater than that of ultraviolet light which typically ranges from 100nm to 400nm. Where, nm is represents nanometer.
Basically, when ignited, a uranium compound burns with a green flame having a wavelength of 4.30 x 10^-7m to 5 x 10^-7m.
A student conducting a calorimetry investigation determines a negative ∆H. What does the negative value indicate about the reaction?
A. The reaction synthesized a single product.
B. The reaction was exothermic.
C. The reaction absorbed energy.
D. The reaction involved decomposition.
Answer:
a
Explanation:
correct
How is the periodic table generally arranged?
Answer:
It is generally arranged by the atomic number
Explanation:
The force of 20 N acts upon a 5kg block. What is the acceleration of the block?
100 m/s/s
4 m/s/s
O 25 m/s/s
O 0.25 m/s/s
Answer:
The answer is 4 m/s²Explanation:
The acceleration of an object given it's mass and the force acting on it can be found by using the formula
[tex]a = \frac{f}{m} \\ [/tex]
where
a is the acceleration
f is the force
m is the mass
From the question
f = 20 N
m = 5 kg
We have
[tex]a = \frac{20}{5} \\ [/tex]
We have the final answer as
4 m/s²Hope this helps you
Help asap!!!!
What are elements in the tall columns of the periodic table called?
A. Representative elements
B. Valence elements
C. Atomic elements
D. Period elements
The elements in the tall columns of the periodic table are called representative elements or main group elements. They exhibit similar chemical properties within their respective groups due to their shared number of valence electrons. The terms "valence elements," "atomic elements," and "period elements" are not commonly used or recognized in the context of the periodic table.
The correct answer is option A.
The elements in the tall columns of the periodic table are called "A. Representative elements," also known as the "main group elements" or "group A elements." These elements are found in groups 1, 2, and 13 to 18 (excluding the transition metals) on the periodic table.
Representative elements are characterized by having similar chemical properties within their respective groups. This similarity arises from the fact that elements within the same group have the same number of valence electrons, which are the electrons in the outermost energy level of an atom. Valence electrons play a crucial role in determining the chemical behavior and reactivity of an element.
The representative elements include the alkali metals (Group 1), alkaline earth metals (Group 2), boron group (Group 13), carbon group (Group 14), nitrogen group (Group 15), oxygen group (Group 16), halogens (Group 17), and noble gases (Group 18). These elements exhibit a wide range of properties, from highly reactive metals to nonmetals and inert gases.
The term "valence elements" mentioned in option B is not commonly used in the context of the periodic table. Valence electrons are indeed significant in determining chemical properties, but they are not specific to the elements in the tall columns. Valence electrons are found in elements across the periodic table.
"Atomic elements" mentioned in option C is a vague term and does not specifically refer to the elements in the tall columns. All elements on the periodic table are atomic in nature, as they are composed of atoms.
"Period elements" mentioned in option D is not a recognized term in the context of the periodic table.
In conclusion, the elements in the tall columns of the periodic table are known as representative elements or main group elements. These elements exhibit similar chemical properties within their respective groups due to their shared number of valence electrons.
Therefore, from the options provided the correct one is A.
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The human eye cannot see anything less than 40 micrometers in size. What is this length in meters?
Answer:
4e-5 is the length in meters
Have a nice day! :)
An aqueous solution is in equilibrium with a gaseous mixture containing an equal number of moles of helium, carbon dioxide, and nitrogen. Rank the relative concentrations of each gas in the aqueous solution from highest to lowest. An aqueous solution is in equilibrium with a gaseous mixture containing an equal number of moles of helium, carbon dioxide, and nitrogen. Rank the relative concentrations of each gas in the aqueous solution from highest to lowest.
[CO2][CO2] > [He][He] > [N2][N2] [N2][N2] > [CO2][CO2] > [He][He] [CO2][CO2] > [N2][N2] > [He][He] [He][He] > [N2][N2] > [CO2][CO2]
Answer:
[CO2] > [N2] > [He]
Explanation:
The relative concentration of CO2, N2 and He depends on the solubility of each gas in water. The more soluble in water a gas is, the greater its concentration in aqueous solution.
Among the gases listed, CO2 is most soluble in water hence it is expected to have the greatest concentration in solution followed by N2. Helium gas is insoluble in water hence it has the least concentration in the aqueous solution.
What is the difference in drawing Lewis Dot
Structures for ionic and covalent bonds?
The Lewis Dot Structure for ionic compounds must demonstrate how the electrons are transported to create the ions in the compound. The Lewis Dot Structures of covalent compounds must demonstrate how the electrons are being shared to finish the octets of each atom in the molecule.
What is an ionic compound ?A chemical compound known as an ionic compound is one that contains ions bound together by the electrostatic forces known as ionic bonding. Despite having both positively and negatively charged ions, or cations and anions, the molecule is generally neutral.
The term "ionic bonding" refers to a bond in which the ionic character is greater than the covalent character, i.e., when there is a significant difference in the electronegativity of the two atoms, which makes the bond more polar (ionic) than in a covalent bond, where the electrons are distributed more evenly.
The Lewis structures are not frequently drawn for ionic compounds due to the electrical motion of electrons.
Thus, The Lewis Dot Structure for ionic compounds must demonstrate how the electrons are transported to create the ions in the compound.
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what is heavier 1 pound of bricks or 1 pound of feathers
Answer:
They are both the same.
Explanation:
ONE POUND of feathers
ONE POUND of brick
Answer:
They are both the same
Explanation:
Even though feathers are lighter they are both 1 pound. Why do you have so many feathers?!?!?
How much heat, in kilojoules, must be added to a 580 g aluminum pan to raise its temperature from 25∘C to 150∘C?
---The specific heat capacity for aluminum is 0.897 J/g∘C.
---Round the answer to two significant figures.
Answer:
Q = 65 kJ
Explanation:
Given that,
Mass, m = 580 g
Initial temperature, [tex]T_i=25^{\circ} C[/tex]
Final temperature, [tex]T_f=150^{\circ} C[/tex]
The specific heat capacity for aluminum is 0.897 J/g°C
We need to find the heat added to the aluminium pan so that its heat raised to a temperature from 25°C to 150°C. It is given by :
[tex]Q=mc\Delta T\\\\Q=580\ g\times 0.897\ J/g^{\circ} C\times (150-25)^{\circ} C\\\\Q=65032.5\ J[/tex]
or
Q = 65.03 kJ
or
Q = 65 kJ
Hence, the heat added to the pan is 65 kJ.
Why can stars be called element factories?
Answer:
They came from the element factories we call stars. Stars are mostly hydrogen throughout most of their lifespans. They are driven by massive and continuous thermonuclear reactions and gravity. ... This extra heat begins to fuse helium atoms into heavier elements like carbon and oxygen and gives new life to the star.
Explanation:
please help
Air masses that form over large bodies of water are moist. What process determines the amount of moisture in an air mass?
Answer:
I don't know if this is right but try it. The amount of water vapor in the air is called absolute humidity. The amount of water vapor in the air as compared with the amount of water that the air could hold is called relative humidity. This amount of space in air that can hold water changes depending on the temperature and pressure.
A student heats 25 mL of water from 20°C to 96°C in a glass beaker. The
model represents the motion of the water molecules during heating.
Explain why some of the water molecules shown in the model have
longer arrows than other water molecules during heating.
Answer:
Because the have acquired energy from the heating process, that is why the start moving faster.
Explanation:
Hello.
In this case, since the initial liquid water molecules have a certain energy content, which makes them move with the relatively medium velocity characteristic in liquid-phase substances, once energy starts being added, it is evidenced that the molecules acquire more energy which is able to make them move faster.
In such a way, since the initial water molecules velocity is marked by a medium range arrows, meaning that the molecules are moving not-so-fast, not-so-slow but the heated water molecules are marked by longer arrows, meaning that they move faster, we infer that such velocity increase is due to the addition of heat due to the heating process from 20 °C to 96 °C (just before boiling).
Regards!
Molecular motion is the action of motion of the molecules or the particles in a specific direction. The molecules start moving faster due to the energy given by the heat.
What are the factors affecting molecular motion?The movement of the molecules or the particles in the system is affected by the temperature and the heat given to the system by the external source.
The initial molecules have relative speed and motion in the system and after the addition of the factors the energy of the motion of the particles gets affected.
When the temperature of the water in the beaker is increased then the average kinetic energy of the molecules also increases and hence the motion of the molecules increases.
The medium ranged arrows depict the average speed of the molecule movement in the medium, while the longer arrows suggest the fast-moving molecules of the water.
Therefore, the heat increases energy and in turn the molecular motion.
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why is water a neutral substance
Answer: Water is considered neutral because the concentration of hydrogen and hydroxide ions is the same
Explanation:
The diagram illustrates photosynthesis. Which best describes what is happening in the area marked X?
Answer:
You forgot to include the diagram use snipping tool to take a picture and upload it
Explanation:
How would a descriptive model of Earth's layers be categorized?
a. abstract model
b. prototype model
c. concrete model
d. conceptual model
A descriptive model of Earth's layers can be categorized as prototype model. Hence, option B is correct.
What is a descriptive model?
A descriptive model describes a system or other entity and its relationship to its environment.
The Earth has different compositional and mechanical layers. Compositional layers are determined by their components, while mechanical layers are determined by their physical properties.
The outermost solid layer of a rocky planet or natural satellite. Chemically distinct from the underlying mantle.
Hence, option B is correct.
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The strength of an acid is affected by the polarity of the bond connected to the acidic hydrogen. The more highly polarized this bond, the more easily the hydrogen is ionized. Electronegative atoms or groups of atoms present in the structure of an acid can act to withdraw electrons and produce additional polarization. Two common groups of acids to which this principle can be applied are oxyacids and carboxylic acids. Arrange the following oxyacids in order of decreasing acid strength. Rank from strongest to weakest acid.
a. HBrO
b. HClO
c. HClO3
d. HClO2
Answer:
Explanation:
Oxyacids are acid containing oxygen; they are also known as acid-alcohol or acid-phenol. As said earlier, the strength of these acids increases with increases in the polarity of these compounds. So, what makes the polarity is as a result of the electronegative substituents attached to it. Halogen family possesses the highest electronegativity in the periodic table, and electronegativity decreases down the group.
The ranking of the oxyacids in order of decreasing acid strength from strongest to weakest acid is:
HClO3 > . HClO2 > HClO > HBrO
Briefly explain why the bulk temperature of the water remains low (at room temperature)
The purpose for witch something is designed or exists
Answer:
to help
Explanation:
to help
will mark brainliest, please hurry! :>
When a hydroxyl group is substituted for a hydrogen atom in a hydrocarbon, what type of molecule results?
a.
an alcohol
c.
a carboxylic acid
b.
an amine
d.
a polymer
Answer:
ans. will be a. an alcohol
What change would you expect on the rate of the SN2 reaction of 1-iodo-2-methylbutane with cyanide ion if the nucleophile concentration is halved and the alkyl halide concentration is doubled
Answer:
The rate of reaction remains the same, no change is observed
Explanation:
Remember that for an SN2 reaction, the rate of reaction depends both on the concentration of the alkyl halide and the concentration of the nucleophile.
Hence we can write; Rate = k [Alkyl halide][NaI]
This implies that if we half the concentration of the nucleophile and double the concentration of the alkyl halide, the rate of reaction just remains the same since the reaction is bimolecular and first order in both alkyl halide and nucleophile
When an objects volume is made smaller and it’s mass remains the same it’s density