Answer:
Electrons arrangement change is almost constant down the group, hence nuclear charge is almost constant.
But the energy levels on which electrons are arranged increase down the group, hence shielding or screening effect increases.
What is the atomic number of an element that has seven protons and eight neutrons and seven electrons?
Answer:
Nitrogen has an atomic number of 7 (Z=7) because it has 7 protons in its nucleus. Some nitrogen atoms have an atomic mass number of 15 (A=15). A is the number of neutrons plus protons in the nucleus. However, we already know that there are 7 protons
Answer:
Atomic number = Number of protons = Number of electrons
Atomic number = 7
how was bohr´s atomic model different from those of previous scientists
Answer:
Explanation:
Neils Bohr in 1913 put forward his own model of the atoms based on the quantum mechanics originally developed by Planck.
He assumed the Rutherford's model and suggested that the extranuclear space consists of electrons in specific spherical orbitals around the nucleus. His predecessors and contemporaries did not give this perspective to the atomic model. The orbits/energy levels are designated by letters K, L, M, N .... The maximum number of electrons that can be accommodated by an energy level is 2n² where n is the principal energy level.Answer:
It showed that electrons could jump from one path to another
Explanation:
quiz
With the aid of a balanced chemical equation explain Chemical Reactions and the Types Of Chemical Reaction
Answer:
Answers
1.)reactants: nitrogen and hydrogen; product: ammonia.
2.)reactants: magnesium hydroxide and nitric acid; products: magnesium nitrate and water.
3.)N 2 + 3H 2 → 2NH 3
4.)Mg(OH) 2 + 2HNO 3 → Mg(NO 3) 2 + 2H 2O.
5.)2NaClO 3 → 2NaCl + 3O 2
6.)4Al + 3O 2 → 2Al 2O 3
7.)N 2(g) + 3H 2(g) → 2NH 3(g)
Explanation:
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A chemical reaction is a process in which atoms are rearranged to form new molecules or substances. During a chemical reaction, chemical bonds are broken and formed, resulting in the transformation of reactant molecules into product molecules. The reactants and products of a chemical reaction are characterized by their chemical formulas, which describe the types and numbers of atoms present in the molecules.
A balanced chemical equation is a written representation of a chemical reaction that shows the reactants on the left side of the equation and the products on the right side. The equation is balanced by adjusting the coefficients (the numbers in front of the chemical formulas) so that the number of atoms of each element is the same on both sides of the equation. This ensures that the law of conservation of mass is obeyed, which states that matter cannot be created or destroyed during a chemical reaction.
There are several types of chemical reactions, including:
Decomposition reactions: These reactions involve the breakdown of a single compound into two or simpler substances. An example of a decomposition reaction is the thermal decomposition of water to form hydrogen and oxygen gases:
2H2O (l) -> 2H2 (g) + O2 (g)
Displacement reactions: These reactions involve the replacement of one element with another element in a compound. An example of a displacement reaction is the reaction of zinc with hydrochloric acid to form zinc chloride and hydrogen gas:
Zn (s) + 2HCl (aq) -> ZnCl2 (aq) + H2 (g)
Redox reactions: These reactions involve a transfer of electrons from one species to another. An example of a redox reaction is the reaction of magnesium with oxygen to form magnesium oxide:
2Mg (s) + O2 (g) -> 2MgO (s)
Combination reactions: These reactions involve the combination of two or more substances to form a single compound. An example of a combination reaction is the reaction of hydrogen and oxygen to form water:
2H2 (g) + O2 (g) -> 2H2O (l)
Acid-base reactions: These reactions involve the transfer of a proton from an acid to a base. An example of an acid-base reaction is the neutralization of hydrochloric acid with sodium hydroxide to form water and sodium chloride:
HCl (aq) + NaOH (aq) -> H2O (l) + NaCl (aq)
What is the charge of the nucleus ? Why ?
Answer:
A nucleus is a positive charge
Explanation:
A nucleus is made up of protons and neutrons. Protons have a positive charge and neutrons have a neutral charge.
how does the ocean affect the climate of nearby mountain ranges ?
give me a good paragraph ! for extra points pls
Answer:
Prevailing winds (sea breeze) from the ocean push warm moist air against the mountain & it moves up. As the moist air rises, it begins to get cooler and cooler due to the high altitude. ... Dry Air Since the air already lost its moisture, the humidity on this side is low & plants get very little water.
Explanation:
The oceans influence climate by absorbing solar radiation and releasing heat needed to drive the atmospheric circulation, by releasing aerosols that influence cloud cover, by emitting most of the water that falls on land as rain, by absorbing carbon dioxide from the atmosphere and storing it for years t
Rico is doing an experiment. He makes a solution of calcium carbonate in a beaker of 200 mL of water at room temperature (25 °C). He adds a small amount of lemon juice to the solution and a chemical reaction begins. Rico reduces the temperature of the solution by 10 °C by adding ice. As the solution cools, what will happen to the chemical reaction?
The question is incomplete, the complete question is;
Rico is doing an experiment. He makes a solution of calcium carbonate in a beaker of 200 mL of water at room temperature (25 °C). He adds a small amount of lemon juice to the solution and a chemical reaction begins. Rico reduces the temperature of the solution by 10 °C by adding ice. As the solution cools, what will happen to the chemical reaction?
A. The chemical reaction will stop suddenly.
B. There will be no change in the rate of the chemical reaction.
C. The chemical reaction will slow as the water cools.
D. The speed of the chemical reaction will increase as the water cools.
Answer:
C. The chemical reaction will slow as the water cools.
Explanation:
The rate of a chemical reaction is dependent on the temperature of the reaction system. This derives directly from the collision theory of chemical reaction.
The higher the temperature of the system, the more frequently the particles collide and the faster the rate of reaction.
As the temperature is decreased, the rate of reaction decreases simultaneously. Therefore, as Rico decreases the temperature from 25 degrees to 10 degrees, the rate of reaction decreases accordingly.
Which properties most likely belong to a metal?
A. brittle and dull
B. liquid and clear
C. ductile and malleable
D. gaseous and unreactive
The properties most likely belong to a metal are ductile and malleable.
What is ductility and Malleability?Malleability - Those metals that can be beaten into thin sheets with a hammer or any heavy object. For example - Cu, Au etc
Ductility- The property of the metals which can lead the metals to form them into wires.
Conductivity - Conductivity is the measure of the ease at which an electric charge or heat can pass through a material. For example - Metals are good conductors of heat and electrolytic solution is conductors of electricity.
Metals have many other properties including the given above, like sonority, lustrous surface, very hard etc.
Therefore, The properties most likely belong to a metal are ductile and malleable.
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What type of reaction is this:
C + 02 --> CO2
Answer:
synthesis reaction
Explanation:
A + X --> AX
Answer:
Combustion reaction
Explanation:
WILL GIVE BRAINLIEST THANK YOU
Choose all the answers that apply.
Which of the following are types of changes that can happen in the rock cycle?
metamorphic to metamorphic
igneous to sedimentary
sedimentary to metamorphic
igneous to metamorphic
metamorphic to sedimentary
Answer:
igneous to metamorphic
sedimentary to metamorphic
State and explain each law of motion.
Answer:In the first law, an object will not change its motion unless a force acts on it. In the second law, the force on an object is equal to its mass times its acceleration. In the third law, when two objects interact, they apply forces to each other of equal magnitude and opposite direction
Explanation:
Answer:
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Explanation:
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Jack is melting butter in a pan. He observes a clear liquid with many solid particles floating in it. Based on Jack's observation, what conclusion can be made about butter?
Answer:
B.
Butter is a mixture of pure substances.
Explanation:
just poop and you will see
I need the answer for number 17 pls
What is the answer to question 7, NH4C2H3O2
Answer:
Ammonium acetate was not sure at first but it was Ammonium acetate sorry i was confused at first
Hope this helps :D
CARDS
In a science experiment, Marisa concludes that no chemical reaction has occurred. What evidence would support
this conclusion?
A. the mass and total number of atoms were conserved
B. no energy were released
C. a new element was created
D. no new substance was formed
Answer:d
Explanation:
People's actions can cause air pollution. People can plant trees to help reduce air pollution.
How does planting trees help reduce air pollution?
O A Trees take in nitrogen and dust.
B. Trees block sunlight from reaching the ground.
O c Trees produce oxygen and take in carbon dioxide.
D. Trees add nutrients to the soil that other living things need
Answer:
c
Explanation:
Bases form __________ ions in water.
a.
hydrogen
c.
positive
b.
hydroxide
d.
both a and c
Answer:
d
Explanation:
Answer:
a. hydrogen
Explanation:
30 POINTS!! ILL MAKE BRAINLIEST!!
Thanks! also that's a lot use a calculator.!
Why do positive ions have a positive charge?
Answer:
Ions form when atoms gain or lose electrons. Since electrons are negatively charged, an atom that loses one or more electrons will become positively charged; an atom that gains one or more electrons becomes negatively charged. Ionic bonding is the attraction between positively- and negatively-charged ions.
Type the correct answer in the box, Express the answer to three significant figures. Given: N2 + 3Cl2 + 2NC3, AH = 464 kJ/mol Use the given bond energies and the periodic table to calculate the energy change in the reaction. The AH when 85.3 grams of chlorine reacts in the given reaction is kilojoules.
Answer:
The given chemical reaction is:
Δ∑BE(reactants)-∑BE(products)
= {(941 kJ/mol) + (3 * 242 kJ/mol)} -[{2*(3*200 kJ/mol)}]
= 467 kJ/mol
Calculating the change in heat when 85.3 g chlorine reacts in the above reaction:
Moles of chlorine =
= 1.20 mol
Heat change when 1.20 mol chlorine reacts
=
Explanation:
Answer:
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Explanation:
Determine the number of seconds in one week.
Answer:
604,800 seconds in a week
Explanation:
86,400 seconds in a day
86,400 × 7 = 604,800
48g of magnesium reacts with four moles of sulfuric acid. determine which reactant is the limiting reactant
Answer:
Magnesium is limiting reactant.
Explanation:
Based on the reaction:
Mg + H₂SO₄ → MgSO₄ + H₂
1 mole of Mg reacts per mole of sulfuric acid
To find limiting reactant we need to convert mass of magnesium to moles. If moles of Mg > moles sulfuric acid, sulfuric acid is limiting reactant and vice versa.
Moles Mg -Molar mass: 24g/mol-:
48g Mg * (1mol / 24g) = 2moles
As there are just 2 moles of Magnesium, just 2 moles of H₂SO₄ will react and 3 moles will remain. That means:
Magnesium is limiting reactant.5. __HCl + __NaOH-> __NaCl + __H2O
6. __FeS + __HCl-> __H2S + __FeCl2
7. __C2H4 + __O2-> __CO2 + __H2O
What are the balanced equations?
Answer:
5. balanced (1,1,1,1)(double replacement)
6. 1,2,1,1 (double replacement)
7. 1,3,2,2 (combustion)
Explanation:
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Given a force of 100.00 N and an acceleration of 5 m/s2, what is the mass of the object?
Answer:
20 kgExplanation:
The mass of the object can be found by using the formula
[tex]m = \frac{f}{a} \\ [/tex]
f is the force
a is the acceleration
From the question we have
[tex]m = \frac{100}{5} = 20 \\ [/tex]
We have the final answer as
20 kgHope this helps you
Describe what the greenhouse effect is and how it is caused on a molecular level.
The greenhouse effect can be cause as the process by which the temperature of the surface of the earth increases because of the earth's atmosphere. On the molecular level, greenhouse effect will be caused by the molecules of the some chemicals, called as the greenhouse gases.
When the some of the infrared radiation coming from the Sun and passes through the atmosphere, but the most of it absorbed and it will re-emitted in all the directions by the greenhouse gas molecules and the clouds. This effect is to warm the Earth's surface and will the lower atmosphere.
As the infrared radiation and the heat will be trapped and the recycled in between the atmosphere and the planet, it will generates the heat cycle.
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What are the principal energy level? And what do they represent?
Answer:
the principal energy level of an electron refers to the shell or orbital in which the electron is located relative to the atoms nucleus. the first element in a period of the periodic table introduces a new principal energy level.
Explanation:
the electrons surrounding an atom are located in region around the nucleus called "energy level".
If the length, width, and height of a box are 9.50 cm, 6.75 cm and 3.50 cm, respectively, what is the volume of the box in units of milliliters and liters?
(a) How many mL will the box contain?
(b) How many L will the box contain?
Answer: 1cm³= 1mL
Explanation:
Suppose an environmental change that causes the soil color to become much different occurs in both environments. Which of the following is true?
A.
Population 1 is more likely to adapt and survive than population 2 because there is more variation related to body color in population 1.
B.
The individuals in both populations will adapt within their lifespans to exhibit a darker body color because this will increase their ability to survive.
C.
Population 2 is more likely to adapt and survive than population 1 because there is more variation related to body color in population 2.
D.
Both populations are equally as likely to adapt and survive because both populations exhibit the same level of body color variation.
Answer: the answer is A
Explanation:
If the actual yield of sodium chloride from the reaction of
8.3 g of sodium and 4.5 g of chlorine is 6.4 g, what is the percent yield?
Answer:
86%
Explanation:
Calculate the theoretical yield from the mass of each reactant. The lesser amount is the theoretical yield. Then use the following formula to calculate the percent yield: % yield = actual yield/theoretical yield X 100.
what percent of the sun's energy is used by the living organism on earth
a. 1%
b. 10%
c. 20%
d. 35%
e. 50%
Which statements apply to density? Check all that apply.
O Density is a chemical property of an object.
The density of an object is constant.
Density is a derived unit of measure.
Density is the sum of the mass and volume of an object.
The density of an object determines whether it will sink or float.
Answer:
the density of an object determines whether it will sink or float
Answer:
Its B,C,E
Explanation: