Answer:
204.4 amu.
Explanation:
30% of thallium will be multiplied by the mass number of thallium-203(203). 70% thallium will be multiplied by the mass number of thallium-205(205).
Then you will add them up.
So, (0.30x203) + (0.70x205) = 204.4 amu.
The metal thallium have two isotopes with different masses. The average atomic mass of thallium is 204.4.
What is isotopes?Isotopes are atoms with same atomic number and different mass number. For example hydrogen have three isotopes namely proton, deuteron and triton with masses 1, 2 and 3 au respectively.
The average atomic mass of an atom can be calculated from the percentage abundance and masses of its isotopes as given below:
atomic mass = ∑ (% abundance/100) mass
The mass of metal thallium is calculated as follows:
Atomic mass of thallium = [tex][\frac{30}{100}\times 203] + [\frac{70}{100}\times 205]= 204.4[/tex]
Hence, the average atomic mass of thallium is 204.4 au.
To learn more about isotopes, refer the link below:
https://brainly.com/question/21536220
#SPJ2
Elements and compounds at the beginning of a reaction are ____.
They are called the Reactants
A reactant? If i understood correctly.
Name an element that has the same number of electron energy levels as Calcium (Ca)?
Answer:
aluminum?
Explanation:
HELP QUICK An unknown substance is a liquid and is red in color.
How can you determine if the unknown is a mixture or a pure substance?
haz un mapa conceptual y explique con imagenes las formas , estructuras y tipos de celulas vegetales que existen en la naturaleza.
Necesito ayuda es para hoy.
Answer:
Si
Explanation:
The prefix 'sub' means 'below'. Why are particles smaller than an atom called subatomic particles.
Answer:
Because they are smaller than an atom
Explanation:
(a) Given that density is usually expressed in the units of g/cm3
, calculate the density of a cube of plastic that
has a mass of 2.331 g and an edge length of 1.500 cm (volume of a cube is V = l^3).
(explain/or do density(calculate it) find volume first. then show work of density divided by volume give proper units.) (Density is a physical property of a molecule that’s measured as mass per unit volume.) (Measurement in chemistry. Think about the density of different substances. PLEASE SHOW WORK)
Answer:
0.690g/cm^3
Explanation:
•Mass: 2.331g
•Volume: 3.375 cm^3
One side is 1.5cm.
1.5^3
3.375cm^3
•Density: Mass/Volume
Mass = 2.331g
Volume = 3.375cm^3
2.331g/3.375cm^3
0.690g/cm^3
Density: 0.690g/cm^3What is the correct ratio of coefficients to balance this chemical equation? 8 1:12 01:2:13 O 1-2-3 thing 0 2:43
Answer:
2:4:3
Explanation:
The coefficient to balance this chemical equation is 2:4:3
Answer: very important
Explanation: where did u get this worksheet from
the basic principles of atomic theory were first conceived by:
The ancient atomic theory was proposed in the 5th century bc by the Greek philosophers Leucippus and Democritus and was revived in the 1st century bc by the Roman philosopher and poet Lucretius.
Hydrochloric acid has the
chemical formula HCI. Does this
information make you think that
hydrochloric acid is an element,
compound, or mixture
Answer:
its a mixture
Explanation:
I can't explain why
Mendeleev placed thallium (Tl) in the same group as lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs). However, the modern periodic table doesn’t place thallium in this group. Use the periodic table to find the properties of thallium. Explain why Mendeleev might have grouped thallium in the same group as lithium and sodium. Also explain how thallium is different from the other five elements.
Answer:
When observing how thallium reacts with the air of the earth's atmosphere, its hardness or resistance resembled sodium, it was not investigated further to classify it correctly
Explanation:
Now it is known that they contain different numbers of valence electrons and that thallium is a heavy metal like lead and that they have similar characteristics except for their melting point where thallium is higher.
Mendeleev might have grouped thallium in the same group as lithium and sodium due to many reasons:
Since, all are metals so they need to be placed in the same group.The particular group is referred to (group one) is actually the most reactive metals on the periodic table. These are the elements that most easily loose their electron from their outer valence shell. Thus each element can easily give up their valence electron in a reaction to form a positive ion. These are the most easily reactive in this way.When observing how thallium reacts with the air of the earth's atmosphere, its hardness or resistance resembled sodium, it was not investigated further to classify it correctly.Now it is known that they contain different numbers of valence electrons and that thallium is a heavy metal like lead and that they have similar characteristics except for their melting point where thallium is higher.
Learn more:
brainly.com/question/17169639
used by rutherford in his experiment; made of two protons and two neutrons
Name the form of carbon used for absorbing poisonous gases and purification of noble gases
9. An element Q with electronic configuration 2.8, 2 reacts with elements R. with electronic configuration 2, 8, 7 to form an ionic compound. The likely formula of this compound is:
Answer:
QCl2
Explanation:
Q should belong to group 2 so valency is 2
R should belong to group 17 so valency is 1
Why can't molecules have thermal energy?
Answer:
Thermal Energy, also known as random or internal Kinetic Energy, due to the random motion of molecules in a system. Kinetic Energy is seen in three forms: vibrational, rotational, and translational. Vibrational is the energy caused by an object or molecule moving in a vibrating motion, rotational is the energy caused by rotating motion, and translational is the energy caused by the movement of one molecule to to another location.
How could understanding the unified structure of atoms help you better understand an element that was unfamiliar to you?
Answer:
Well,You have to understand pretty much everything, If you know the number of protons or electron then you will know its atomic number,and if you know the number of protons and neutrons then you will know the mass of the element. so, once you grasp these concepts, you can better understand new elements.Explanation:
8. Calculate density and record it in Table 1for each of the minerals. (Make sure to use the correct significant figures)
Answer:
.....
Explanation:
BECAUSE ....
WILL MARK AS BRAINLIEST IF CORRECT
1) How do valence electrons impact the type of bonds an atom makes?(1 point)
a. A large number of valence electrons means the atom will share electrons; a small number of valence electrons leads to transferring from one atom to another.
b. An atom wants a full outer shell of valence electrons, so it will either transfer or share electrons depending on what the other atom needs.
c. An atom wants an empty outer shell of valence electrons, so it will either transfer or share electrons depending on what the other atom needs.
d. A small number of valence electrons means the atom will share electrons; a large number of valence electrons leads to transferring from one atom to another.
2) Use your knowledge of valence electrons and how they affect bonds to figure out how carbon (Group 14) and oxygen (Group 16) would be attached to one another. In carbon dioxide (CO2), how is the compound structured? (Use “–” to represent a single bond and “=” to represent a double bond.)(1 point)
a. C–O–O
b. C=O–O
c. O=C–O
d. O=C=O
3: Methane’s chemical formula is CH4. Is there a bond between any of the hydrogen atoms? Why or why not?(1 point)
a. Yes, there is because they form a long chain in order to all have stable outer energy shells.
b. No, there is not because it would form H2 instead of methane if hydrogen bonded with itself.
c. No, there is not because carbon needs four bonds, so it bonds with each hydrogen atom; hydrogen only forms one bond.
d. Yes, there is because there are one too many hydrogen atoms for carbon to handle alone, so one hydrogen must bond with another.
4: In hydrogen peroxide (H2O2), which option best shows how the atoms are ordered?(1 point)
a. O–H–O–H
b. H–O–O–H
c. O–H–H–O
d. H–O–H–O
Answer:
1. How many electrons does hydrogen need in order to have a full shell of valence electrons?...two
2. How do valence electrons impact the type of bonds an atom makes?...An atom wants a full outer shell of valence electrons, so it will either transfer or share electrons depending on what the other atom needs.
3.Use your knowledge of valence electrons and how they affect bonds to figure out how carbon (Group 14) and oxygen (Group 16) would be attached to one another. In carbon dioxide (CO2), how is the compound structured? (Use “–” to represent a single bond and “=” to represent a double bond.)...O=C=O
4. Methane’s chemical formula is CH4. Is there a bond between any of the hydrogen atoms? Why or why not?...No, there is not because carbon needs four bonds, so it bonds with each hydrogen atom; hydrogen only forms one bond.
5. In hydrogen peroxide (H2O2), which option best shows how the atoms are ordered?...H-O-O-H
Explanation:
Valence electrons are found on the outermost shell of an atom and determines the kind of bonds the atom can form.
When an atom has a large number of valence electrons, it is energetically more favorable for the atom to share electrons rather than to transfer electrons to another atom. Atoms with less valence electrons transfer electrons from one atom to another.
Since carbon is a member of group 14 and oxygen is a member of group 16, it follows that carbon can share four electrons with two oxygen atoms as shown in the structure O=C=O.
Carbon is always tetravalent in all its compounds. This means that one carbon atom must form four bonds. It follows that the carbon atom in CH4 forms four bonds with the four hydrogen atoms hence there are no bonds between hydrogen atoms in CH4.
H2O2 contains the peroxide (O-O) bond. It follows that its correct structure must be H–O–O–H.
Learn more: https://brainly.com/question/928042
WILL MARK AS BRAINLIEST IF CORRECT
3. Which graph indicates that one of the runners started 10 meters ahead of the other?
A
B
30
Distance from starting line (meters)
Distance from starting line (meters)
2
1
2
Time seconds)
The seconds
с
D
Distance from starting line (meters)
Distance from starting line (meten
GE
1
2
Time (seconds)
The seconds)
A graph A
O B. graph B
O C. graph
O D. graph D
Answer:
A
Explanation:
I think, I hope it is correct
please help! qqqqqqqq
Answer:
sorry Hindi ko po alam ang sagot
if you think about similarities between elements instead of differences, how can that make understanding matter a little bit easier?
Which marine ecosystem depends on upwelling from the seafloor to maintain its high productivity?
Answer:n some ways, upwelling can be a mixed blessing to coastal ecosystems. It can infuse coastal waters with critical nutrients that fuel dramatic productivity,
Explanation:
Coral reefs is the marine ecosystem which depends on upwelling from the seafloor to maintain its high productivity.
What is an ecosystem?Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.
Learn more about ecosystem,here:
https://brainly.com/question/1061425
#SPJ2
Provide a particle-level explanation for the relationship between pressure and temperature
when the alcohol is in the gas phase.
The conservation of energy allows finding the relationship between pressure and temperature is:
Pressure is directly proportional to the temperature of the alcohol in the gaseous state.
Pressure is defined by the relationship between force and area of application.
P =[tex]\frac{F}{A}[/tex]
Where P is the pressure, F is the force and A is the area.
In the case of alcohol in the gaseous state, the mechanical energy of the molecules is only kinetic energy, it is related to temperature by the Boltzmann equation.
Em = K = [tex]\frac{3}{2}[/tex] kT
½ m v² = 3/2 k T
v² = [tex]\frac{3 k T}{m}[/tex]
Where m is the mass, v the velocity of the particles, k the Boltzmann constant and T the absolute temperature.
From this equation we see that as the temperature increases, the speed of the alcohol molecules also increases.
Using the relationship between the impulse and the change of momentum we can find the mean force.
I = F t = Δp
Where I impulse, F is the force, t is the time, Δp is the change of momentum.
if we assume elastic collisions the amount of initial and final moment are equal.
[tex]F = \frac{2p}{t} \\F = \frac{2m}{t} v[/tex]
If we assume that the molecules go at a constant speed.
v = d / t
t = d / v
Let's substitute.
[tex]F = \frac{2m}{d} v^2[/tex]
We substitute in the pressure equation.
P = 2m / Ad v²
[tex]P = \frac{6k}{ A d} \ T[/tex]
In conclusion using the conservation of energy we can find the relationship between pressure and temperature is:
Pressure is directly proportional to the temperature of the alcohol in the gaseous state.
Learn more here: brainly.com/question/20638378
for a neutralization reaction, would you expect the magnitude of q to increase, decrease, or stay the same if the concentration of only the acid were doubled? why?
For a neutralization reaction, the value of q(heat of neutralization) is doubled when the concentration of only the acid is doubled.
A neutralization reaction is a reaction in which an acid reacts with a base to yield salt and water. Ionically, a neutralization reaction goes as follows; H^+(aq) + OH^-(aq) ------> H20(l).
The heat of neutralization (Q) of the system depends on the concentration of the solutions. Since Q is dependent on concentration, if the concentration of any of the reactants is doubled, more heat is evolved hence Q is doubled.
Learn more: https://brainly.com/question/10323185
Answer:
Stay the same
Explanation:
If only the concentration of acid were doubled no additional neutralization reaction would occur
What is the mass of 15.0 moles of gold?
Answer:This Should Be the Answer :)
Explanation:
iven: Molar mass of Au = 196.96 g/mol. The Number of moles = 15.3 moles. Hence, 15.3 moles of Au contains 3.01 103 g of Au.
Which condition must be met for conduction to occur?
A:particles must be large
B:articles must be small
C:particles must be in contact
D:particles must be spread apart
Answer:
D
Explanation:
when you boil water in a pot and put a lid or something meatal over it when it reaches a certain temperature it gets steamy and during that it will get hyper and run around in circles and will go up but since the meatal or glass lid is there it will stop it and you will see water droplets on the inside.
Answer:
d
Explanation:
What do polar compounds and ionic compounds have in common?
Answer:
In what way is a polar-covalent bond similar to an ionic bond? There is a difference between the electronegativities of the two atoms in both types of bonds that results in electrons being more closely associated with the more electronegative atom.
Explanation:
please help! will give brainliest!!! match each of the terms on the right with the letters on the right.
Which correctly explains the relationship between predators and prey?
when the number of prey increase the number of predators will increase
when the number of prey decrease, the number of predators will increase
when the number of prey increase, the number of predators will decrease
BRAINLIESTTT
Answer:
When the number of prey increase the number of predators will increase.
Explanation:
This is because the predators have more food available, which will make their population grow.
100 points pls helpppppp?
Answer:
It’s the chemical change then a new substance is formed.
Explanation: