The column number of an element in the periodic table is generally determined on the basis of the number of valence electrons. The elements in the same column have similar chemical properties.
What are valence electrons?The electrons present in the outermost shell of an atom which take part in chemical reactions are called the valence electrons. These electrons are responsible for the interaction between the atoms and the formation of chemical bonds.
The valence electrons of an atom also gives us an idea about the chemical properties of elements like valency, the number of unpaired electrons present, etc. The column number of an element is mainly determined on the basis of number of valence electrons.
The elements are placed in vertical columns in the periodic table. There are 2 electrons in the outermost shell of Alkaline earth metals. So they belong to second column.
Thus it is the valence electron which determines the column number.
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find the volume. mass is 9.75 g and the density is 15.6 g/cm3
Answer:
1.6cm3
Explanation:
density = mass/volume
15.6g/cm3= 9.75 g/volume
15.6/9.75 = volume
1.6cm3 = volume
HELP PLEASE, I NEED THIS BY TODAY!
If you have a 10 gram sample of uranium-235 how much would still be uranium-235 after 1407.6 million years?
Answer:
2.48 g
Explanation:
From the question given above, the following data were obtained:
Original amount (N₀) = 10 g
Time (t) = 1407.6 million years
Amount remaining (N) =?
Next, we shall determine the rate of decay (K) of uranium-235. This can be obtained as follow:
NOTE: Uranium-235 has a half life of 700 million years.
Decay constant (K) =?
Half life (t½) = 700 million years
K = 0.693/t½
K = 0.693/700
K = 9.9×10¯⁴ / year
Therefore, Uranium-235 decay at a rate of 9.9×10¯⁴ / year.
Finally, we shall determine the amount of Uranium-235 remaining after 1407.6 million years as follow:
Original amount (N₀) = 10 g
Time (t) = 1407.6 million years
Decay constant (K) = 9.9×10¯⁴ / year
Amount remaining (N) =?
Log (N₀/N) = kt /2.3
Log (10/N) = (9.9×10¯⁴ × 1407.6) /2.3
Log (10/N) = 0.60588
10/N = antilog (0.60588)
10/N = 4.04
Cross multiply
10 = 4.04 × N
Divide both side by 4.04
N = 10/4.04
N = 2.48 g
Therefore, 2.48 g of uranium-235 is remaining after 1407.6 million years.
If you have a 10 gram sample of uranium-235 there would still be uranium-235 after 1407.6 million years - 2.5 grams.
The half-life of U-235 is the time it takes for half the U to decay. We know that U-235 has 703.8 million years as its half-life which means it takes 703.8 million years to half of its initial amount.
After one half-life, half (50 %) of the original amount will remain. After a second half-life, half of that amount (25 %) will remain, and so on.We can construct a table as follows:
No. of Fraction Amount
half-lives t/(yr × 10⁶) remaining remaining/g
1 703.8 ½ 10/2 = 5
2 1407.6 ¼ 10/4 = 2.50
Thus, the correct answer is - 2.5 grams.
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Round off the following quantities to the number of significant figures indicated in parentheses: 69.733 g (2)
Answer:
70
Explanation:
There are 5 significant figures in the problem. Since it has a decimal point, we start on the left hand side and work our way to the right. You would end up at 69, but then you have to round up since the next number is a 7, which is greater than or equal to 5.
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How is kinetic energy affected by temperature
Answer:
Temperature affects the kinetic energy in a gas the most, followed by a comparable liquid, and then a comparable solid. The higher the temperature, the higher the average kinetic energy, but the magnitude of this difference depends on the amount of motion intrinsically present within these phases
Explanation:
I just know lol
The reaction between a strong acid and a weak base produces a salt, but water is not usually formed because:
the reaction is too hot and water evaporates
there is no hydrogen present to form water
the acid is not strong enough to form water
weak bases tend not to be hydroxides
Answer:
3
Explanation:
A car drives with constant speed of 112km/h. How long will it take to travel to distance of 56 kilometers?
112 km is travelled by car in 60 minutes
1 km is travelled by car in 60/112 minutes
56 km is travelled by car in 60/112*56 = 30 minutes = 0.5 hours
Explanation:
trial 2, 2.68 g/cm/3 trial 3, 2.84g/cm/3. aluminum has a density of 2.70g/cm/3 calcute the percent error for each trial.
Answer:
trial 2: 0.74
trial 3: 5.19
I think but the equation for sloving percent error is:
(true value - determined value)/true value * 100
Explanation:
how many significant figures in 12.030?
Answer:
5
Explanation:
because the 0 is Sig because there is a point and other numbers
Which of the samples pictured is most likely a nonmetal?
Answer:
c
Explanation:
Answer:
it is c because its a hard one and you should know what that is and it is a nonmetal even if not exactly its to be slightly
Explanation:
6.Think about where you live now or where you have lived in the past; use complete sentences to describe this environment and the weather. What building materials do you believe would work well to build a home in that area? Explain why you chose these materials.
Answer and Explanation:
I have always lived in the same region. The region where I live is flat and stable, the site has asphalt and the climate is tropical with a long summer and poorly defined seasons. My region does not have drastic changes and temperature and the climate is hot most of the year. For this reason, it is necessary to use materials that are thermal insulators, on the contrary we need to use materials that are not good thermal insulators such as concrete blocks, bricks, cement and ceramics, we will also need common tiles and rafters to support them.
which best represents a particle containing 28 protons, 26 electrons,and 34 neutrons?
Answer:
This question lacks options, but the question can be answered based on knowledge of proton, electron and neutron number. The answer is:
62 Ni2+ particle
Explanation:
Nickel is a chemical element with atomic number 28. This means it has 28 electrons and 28 protons in its neutral atom. However, the isotope of nickel being described in the question has a mass number of 62. The mass number is calculated by adding the proton number with the neutron number. That is;
Mass number = number of protons + number of neutrons
Mass number = 28 + 34
Mass no. = 62
An element with mass number 62, which has lost two electrons to become positively charged (two positive charges) is described in the question. Hence, the particle that best fits this description is positively charged Nickel particle (Ni2+).
Ni2+ has 28 protons, 26 electrons (reduced by 2) and 34 electrons.
Note that, the 2+ charge is as a result of the loss of two electrons, hence, reducing the electron number by 2.
Betty drew the life cycle of a butterfly for a science exhibition. The life cycle showed the various stages of growth before the egg turns into a butterfly. What type of model did Betty use?
Answer:
Conceptual
Explanation:
A conceptual models are graphical representation of the biological or physical system or another natural phenomenon. It is helping people to understand, imitate and make connections with natural phenomena. The given situation is an example of a conceptual model because it is represented in a graphical way and represents the basic biological events of the actual transformation of a butterfly (transforming a young adult insect into a young adult worm).Answer:
Conceptual
letter B
a table that compares the properties of suspensions, colloids, and solutions.
Answer:periodic table
Explanation:
A researcher is measuring changes in the density of the upper atmosphere over time. Which units should be used for the density measurements?
Answer:
lbm/ft³ or psi/ft
Explanation:
The description in the question shows the density to measured is that of gases (upper atmosphere). The density of a gas can be described as the mass of the gas divided by the volume of the gas at a certain temperature and pressure. It's unit can be represented as lbm/ft³ or psi/ft.
NOTE:
"lbm" means "lean body mass" which is a unit for mass or weight and can be described as the pound mass
"psi" means "pound per square inch"; is also a unit for mass or weight
The law of conservation of energy states that energy can neither be created nor destroyed; however, if you stretch out a ball in your hand and let it freely drop, the ball will not quite bounce back up to the height you dropped it from. Which of the following best explains why this happens? *
The pull of gravity negates the law of conservation of energy.
Some of the energy has to be used up to push the ball back into the air, destroying it forever.
The ball falls too quickly, so the energy does not have enough time to fully recharge.
Some of the energy is released into the air as heat (thermal energy) due to friction.
which answer is it? help
Answer: the last one:)
Explanation: energy cannot be destroyed but can be transfered
(called energy transfer).
Which statement explains how the bands in the crystal of a metal are like atomic orbitals?
A. They both have localized electrons that orbit specific atoms.
B. They both involve ionization of some atoms so bonding can occur.
C. They both have delocalized electrons that move from atom to atom.
D. They both allow electrons to move from lower energy levels to higher energy levels.
Answer:
D
Explanation:
Correct On EDU
Crystal lattice of metals are highly ordered in which the ions and electrons are arranged in a stoichiometric proportion. But,electrons can excite to higher energy levels as they fo in atomic state. Thus , option D is correct.
What is crystal lattice?Crystal are highly ordered structures of solids and is anisotropic in nature with a perfect geometry and crystal lattice units. There will be free electrons present in the interstices spaces and which can be delocalized throughout the lattice results in conduction.
Electrons can acquire energy to excite to the higher energy levels from the lower energy level in a crystal lattice. Electrons are revolving around the nucleus of an atom through definite circular paths of fixed energy.
Electrons in an atom tends to excite to higher energy levels and then will return to the lower energy level by emission of energy in the form of light or heat. This process make the element coloured and conducting as in the case of crystal bands in metals.
Hence, both atoms and metal lattice allow electrons to move from lower energy levels to higher energy levels and option D is correct.
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_____________ dating places the rocks and rock layers in an area into sequential order. ________ dating gives an exact date on rock layers.
Geologic, Absolute
Relative, Geologic
Relative, Absolute
Time, Geologic
Use your knowledge of atomic calculations to complete the chart.
Element
Protons
Neutrons
Electrons
Atomic
Number
3
15
Atomic
Mass
7
31
35
19
28
31
P
ci
Ni
K
Ag
H
39
19
-18
47
OK
1
1
14
14
06
3
Si
w
74
1010
Ne
10
10
Answer:
For hydrogen. H
Explanation:
Atomic number is 1
Proton number is 1
Mass number is 2
Neutron number is 1
5. If a block of wood has a density of 0.6 g/cm3 and a mass of 120 g, what is its volume? (D= M/V)
Answer:
200 cm^3
Explanation:
V = M/D
V = 120g / (0.6g/cm^3)
V = 200 cm^3
In this case, the volume is 200 cm^3.
What is density?
Density is defined as the mass of a material substance per unit volume. The equation for density is d = M/V, where d stands for density, M for mass, and V for volume. Grams per cubic centimetre are a typical unit of density measurement.
For instance, the density of Earth is 5.51 grammes per cubic centimetre, but the density of water is 1 gramme per cubic centimetre. Kg/m3 is another way to measure density (in metre-kilogram-second or SI units). For instance, the air has a density of 1.2 kilogrammes per cubic metre.
Textbooks and manuals provide lists of the densities of common solids, liquids, and gases. The mass of a body may be calculated from its volume using density, and vice versa. The mass is equal to the volume multiplied by the density (M = Vd), whereas the volume is equal to the mass divided by the density (V = M/d).
You may calculate a body's weight by multiplying its mass by the acceleration of gravity, which is typical of more practical significance than its mass. Additionally, there exist tables that indicate the weight of various substances per unit volume; this amount is sometimes referred to as specific weight, weight density, or unit weight.
Instead of referring to the density of a single particle, the term "particle density" refers to the number of particles per unit volume and is typically written as n.
Therefore, here the volume is 200 cm^3.
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A regulation that should be followed to prevent accidents is called safety blank
Answer:
Safety Regulations
Explanation:
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what happened to the color of the sand when it goes through filtration and is quantitative or qualitative
Answer:
Qualitative
Explanation:
I'm not sure if there was another part to the question, but if you are looking at the color of the sand, that is a qualitative observation.
Quantitative statements involve numbers. (Ex: The house has 4 bedrooms.) Qualitative statements describe characteristics. (Ex: The house is blue.)The sum of the number of protons and neutrons in an atom is called the ________ of the element. 1. Molar Mass 2. Atomic number 3. Average atomic mass 4. Mass number
o2 o4 o3 o1
Answer:
The sum of the number of protons and neutrons in an atom is called the Mass number.
Bonnie wants to see if playing music to plants will help them grow taller. She buys 4 of the same kind of plant. They all receive the same amount of sun and water. She plays rap music to plant A, country music to plant B, rock music to plant C, and plant D gets no music at all. Everyday for a week she measures the height of each plant.
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HOPE THAT HELPED.Suppose you set a glass of water in direct sunlight for 2 hours and measure its temperature every 10 min . What type of graph would you use to display your data .
HELP ASAP PLS
Answer:
line graph
Explanation:
The type of graph would be used to display the data is line graph.
What is graph?Graph is defined as a visual representation, such as a picture or diagram, that shows information or values in a structured way. The graph's goal is to visually represent numerical data so that it can be quickly, simply, and clearly understood. As a result, graphs are visual displays of data.
Although a graphical display is easier to understand, data can also be presented as a table. For this kind of data, a line graph will be used. This will show more clearly how the temperature of the water fluctuates over the course of two hours. Time is an independent variable, whereas temperature is a dependent variable.
Thus, the type of graph would be used to display the data is line graph.
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2000 km/sec. Convert that to
m/sec.
Answer:
2000 km/sec
1km=1000m
2000×1000
2000,000 m/sec
2) A wooden block has a volume of 176 cm3 and a density of 18.2 g/ cm3. What is the mass?
Answer:
3,203.2 g
Explanation:
density multiplied by volume gives you the mass, and both cm3 cancel eachother out so you are left with just g.
what is your definition of science?
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how many grams in 5mg
Answer:
0.005
Explanation:
I looked it up
Explanation: It's important to understand that "mg" is the abbreviation
for milligrams and "g" is the abbreviation for grams.
To convert 5 milligrams into grams, we first find the conversion factor
for milligrams and grams, which is 1,000 milligrams = 1 gram.
Next, notice that we're going from a smaller unit,
milligrams, to a larger unit, grams, so we divide.
Whenever we go from a smaller unit to a larger unit,
we will divide by the conversion factor.
So we have 5 mg ÷ 1,000.
When dividing by a power of 10, we can count the number of zeroes
in the power of 10 and move the decimal point that many places to the left.
So our answer is 0.005 grams.
4) If a snail averages about 0.0045 miles per hour (mi/hr), what is his average speed in meters per
second (m/s) (1 mile = 1.6 km)?
Answer:
the answer is 0.00201168 meters per second
As a star uses up its hydrogen supply, it changes from a main sequence star to a -
A.) dwarf
B.) supernova
C.) black hole
D.) giant
As a star uses up its hydrogen supply, it changes from the main sequence star to a Giant. Thus, the correct option for this question is D.
What is a Star?A star may be defined as a type of huge celestial body that is generally constructed of hydrogen and helium that produce light and heat from the churning nuclear forges inside their cores. They are the luminous bodies that are visible in the sky at night.
A giant is a type of star that has utilized its hydrogen supply in its cores and transformed itself into the thermonuclear fusion of hydrogen in the shell that envelops its surroundings.
This creates an outwards force and stimulates fusion that initiates to increase and hence the star can not able to maintain its equilibrium longer.
Therefore, as a star uses up its hydrogen supply, it changes from the main sequence star to a Giant. Thus, the correct option for this question is D.
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