Answer:2
Explanation:
The number of valence electrons for a helium atom is 2. This can be confirmed by looking at the electronic configuration.
Helium atom:Helium is placed in the noble gas series as it has certain properties of it. The atomic number of helium is 2. Thus, it has two electrons in its outermost shell but it has completely filled orbital.
Electronic configuration of He = 1s2
Thus, for drawing the electron dot structure, there are two valence electrons.
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Viruses
are multicellular organisms
cannot survive outside a host
are part of the Protista kingdom
are not considered living because they do not reproduce
Answer:
just see it it will help trust me its my school work
Explanation:
Answer:
C are part of the Protista kingdom
Explanation:
The Protista, or Protoctista, are a kingdom of simple eukaryotic organisms, usually composed of a single cell or a colony of similar cells. Protists live in water, in moist terrestrial habitats, and as parasites and other symbionts in the bodies of multicellular eukaroytes.
Other eukaryotic kingdoms—the Plantae, Fungi, and Animalia—are each believed to be monophyletic . That is, all plants evolved from one ancestral plant, all animals from one ancestral animal, and all fungi from one ancestral fungus. The Protista, however, are not; they are almost certainly polyphyletic and did not arise from a single ancestral protist. Rather, the Protista are a category of miscellaneous eukaryotes, not closely related to each other and not sharing many characteristics, but not fitting any other kingdom of life. Some authorities divide the Protista into as many as twenty-seven phyla, and some feel the Protista should be discarded as a kingdom name, and these organisms divided into as many as twelve kingdoms.
Historically, the Protista were divided into three main categories: the plantlike algae, animal-like protozoans, and funguslike slime molds. This classification persists in many elementary textbooks; however, current molecular evidence indicates that these are not natural groups related by common descent, but groups with merely superficial , deceptive similarities.
Classifying them together is probably no more scientific than it would be to classify bees, birds, and bats in one group simply because they all have wings and fly. The two flagellated protozoan groups called trypanosomes and dinoflagellates, for example, are probably less related to each other than a human is to a fish. Genetic evidence (base sequences in their mitochondrial deoxyribonucleic acid [mtDNA] and ribosomal ribonucleic acid [rRNA]) now indicates that the following are more natural (evolutionarily related) groups of Protista.
These are the most primitive protists. Some lack mitochondria and suggest what the first eukaryotes may have been like, while others have primitive mitochondria that closely resemble bacteria. Some basal Protista without mitochondria are Trichomonas, a vaginal parasite of humans; Giardia, an intestinal parasite; and Entamoeba, the cause of amoebic dysentery. The lack of mitochondria is not necessarily the primitive (original) condition of all these protists, however. Although Giardia lacks mitochondria, it does have mitochondrial genes. Apparently it once had mitochondria, and these genes transferred to its nuclear DNA before the mitochondria were lost.
Basal Protista with mitochondria include Trypanosoma, a genus of blood parasites that cause African sleeping sickness and other diseases; Euglena, a green freshwater flagellated protozoan with chloroplasts; and Physarum, a common terrestrial slime mold.
pls give brainiest my hand hurts ;-:
Where would the most reactive metallic elements of the periodic table be found?
In the B families
On the top of the table
On the far left of the table
Answer:
I think it should be 'On top of the table'
what are the main method of combination of elements ?
Answer: Element can be chemically combined into compound, therefore, a compound consist of two or more elements combined, in definite proportions, by chemical means. Compounds may be formed by combining Adams of their constituent elements by ionic bonds or by covalent bonds.
Explanation:
An object has a fixed volume and shape before it changes state. After the
change, it still has a fixed volume but can now change in shape. Which
change of state has occurred?
A. Gas to liquid
B. Solid to liquid
O C. Liquid to gas
D. Gas to plasma
What part of the atom is involved in chemical reactions?
neutrons
protons
electrons
nucleus
Answer:
electron
Explanation:
hope this helps:)
According to the research, electrons are the part of the atom that is involved in chemical reactions.
What are electrons?It is a subatomic element that is located around the nucleus of the atom, formed by neutrons and protons and is the lightest essential particle that makes up an atom.
In chemical reactions reagents or reactants are involved, specifically in oxidation-reduction reactions electrons are transferred between chemical species, the oxidizing substance loses electrons and the other gains electrons.
Therefore, we can conclude that according to the research, electrons are the part of the atom that is involved in chemical reactions.
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Which of the processes below is a way scientists can accelerate the process
of traditional crossbreeding through inserting beneficial traits in the DNA of a
plant?
Answer:
Genetic Engineering
Explanation:
AP3X
Which has the larger radius, F or F− ?
A. They have the same radius.
B. F
C. F−
D. It is impossible to tell.
Answer is B- F has a smaller radius than F− because an additional electron causes greater repulsion in F− is the correct choice and the nuclear charge the radius of the anion increases.
Explanation: I hoped that helped!
The one that have larger radius is F-. The correct option is C.
What is atomic radius?A chemical element's atomic radius is a measurement of the size of its atom, usually the mean or typical distance from the nucleus's center to the outermost isolated electron.
Because a boundary is not a well-defined physical entity, various non-equivalent definitions of atomic radius exist.
As the number of energy levels decreases down a group, the distance between the nucleus and the outermost orbital increases.
As a result, the atomic radius expands. The ionic radius is the distance between the nucleus and the ion's electron cloud's outer edge.
Because they have fewer shells, F and F- are both smaller than the rest. F- now has one more electron than F, causing the radius to increase.
Thus, the correct option is C.
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Ammonia (NH3) is widely used as a fertilizer
and in many household cleaners. How much
ammonia is produced when 3.55 mol of hydrogen gas react with an excess of nitrogen
Answer:
Mass of ammonia produced = 40.29 g
Explanation:
Given data:
Number of moles of H₂ = 3.55 mol
Mass of ammonia produced = ?
Solution:
Chemical equation:
3H₂ + N₂ → 2NH₃
Now we will compare the moles of ammonia with hydrogen
H₂ : NH₃
3 : 2
3.55 : 2/3×3.55 = 2.37 mol
Mass of ammonia:
Mass = number of moles × molar mass
Mass = 2.37 mol × 17 g/mol
Mass = 40.29 g
is steam a covalent compound or a metallic compound?
Answer:
Steam is a covalent compound.
Explanation:
beacause metallic compound is a compound that contains one or more metal elements bonded to another element. And steam is the invisible vapor into which water is converted when heated to the boiling point.
Which percentage represents the amount of Earth's water that is found in oceans?
A 3%
B. 71%
C.97%
Who uses Ionic compounds?
Collisions between reactant molecules lead to a reaction when the molecules have the correct orientation and
enough kinetic energy
What is the proper compound formula for Hydrogen Cyanide?
A.) H(CN)2
B.) H2(CN)
C.) HCN
D.) H2(CN2)
Answer:
C
Explanation:
Cyanide's formula can be found either on google on on a reference table at the "polyatomic ions" table. Hydrogen, H, has a charge of 1+ when bonded, and cyanide has a charge of 1- overall, so they will be in a one to one ratio while bonded. As such, the equation is HCN.
Round 23.455 cm into 4 significant figures:
cm
HELP ASAP DUE TODAY
Answer:
4. c) Lose only 3 electrons
5. d) Nitrogen.
Your answers are correct
How many moles is 573.28 g of AgCl?
A. 3 mol
B. 5 mol
C. 4 mol
D. 2 mol
Answer:
4 MolExplanation:
Just divide the mass of how much AgCl by the mass per mole to give you the number of moles, 573.28g 143.318gmol−1 AgCl = 4.00molAgCl
Hope this helps! <3
how many moles of N2O5 are produces by reacting 10 moles of O2?
Answer:
4 moles of N₂O₅
Explanation:
Given parameters:
Number of moles of O₂ = 10moles
Unknown:
Number of moles of N₂O₅ produced = ?
Solution:
To solve this problem, we must write the reaction equation first,
2N₂ + 5O₂ → 2N₂O₅
IN the reaction above;
5 moles of O₂ will produce 2 moles of N₂O₅;
10 mole of O₂ will produce [tex]\frac{10 x 2}{5}[/tex] = 4 moles of N₂O₅
Question 1 of 10
What would you need to do to calculate the molality of 10 mol of NaCl in 200
mol of water?
A. Convert the 200 mol of water to kilograms of water.
B. Convert the 200 mol of water to liters of water.
C. Convert the 10 mol of NaCl to grams of NaCl.
O D. Convert the 10 mol of NaCl to kilograms of NaCl.
SUBMIT
Answer:
A. Convert the 200 mol of water to kilograms of water.
Explanation:
To find the molality of 10mol of NaCl in 200mol of water, convert the 200mol of water to kilograms of water.
Molality is one of the several ways of measuring concentration of a solute in a solvent;
Molality = [tex]\frac{number of moles of solute}{mass of solvent}[/tex]
To solve this problem, simply convert the 200mole to mass of water.Why does calcium conduct electricity?
Answer:
calcium is a metal and metals are good conductors of electricity as they contain mobile electrons.
Explanation:
In the reaction 2H2O (l) + 2Cl– (aq) → H2 (g) + Cl2 (g) + 2OH– (aq), which substance is oxidized?
A. H2O
B. Cl
C. H
D. OH
E. None of the Above (This is not a redox reaction.)
Answer:
c
Explanation:
because i asked alexa and it told me hehr
Question:
A. Does this picture show a physical or chemical change? How do you know?
B. Does this picture show a physical or chemical change? How do you know?
Answer:
A. Chemical
B. physical
Explanation:
what is the ratio of mass of 0.7moles of nitrogen gas to 11.2liters of oxigen gas at STP?
Answer:
if a 40.0-gram sample of the gas occupies 11.2 liters of space at STP? A balloon is filled with 5 moles of helium gas.
Explanation:
An element has three naturally occuring isotopes: 90.48% is element-20 (mass = 19.992 amu), 0.27% is element-21 (mass - 20.994 amu), and the remainder is element-22 (mass = 21.991 amu). Calculate the average atomic mass of the element, rounded to three decimal places.
Answer:
Average atomic mass = 20.180 amu.
Explanation:
Given data:
Abundance of X-20 = 90.48%
Atomic mass of X-20 = 19.992 amu
Abundance of X-21 = 0.27%
Atomic mass of X-21 = 20.994 amu
Abundance of X-22 = 9.25%
Atomic mass of X-22 = 21.991 amu
Average atomic mass = ?
Solution:
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) +(abundance of 3rd isotope × its atomic mass) / 100
Average atomic mass = ( 90.48×19.992)+(0.27×20.994)+(9.25+ 21.991 ) /100
Average atomic mass = 1808.88 + 5.668+203.42 / 100
Average atomic mass = 2017.968 / 100
Average atomic mass = 20.180 amu.
Which phrase describes the motion, collisions, and
attractive forces of ideal gas particles?
A) random straight-line motion, KE lost in
collisions, and strong attractive forces
B) random curved-line motion, KE lost in
collisions, and no attractive forces
C) random curved-line motion, no KE lost in
collisions, and strong attractive forces
D) random straight-line motion, no KE lost in
collisions, and no attractive forces
Answer:
B
Explanation:
help meeeee brainliest for whoever helps
Answer:
no
Explanation:
Answer:
All A's
Explanation:
it might sound sus but it all a's
Sodium is a non-metal
A. True
B. False
Answer:
false
Explanation:
...................
its a metal
Which statement best explains why the atmosphere is considered an open system?
Answer:
The answer is A
Explanation:
Trial and error :P
Answer: The answer is B. Energy and matter can enter and leave.
Explanation:
What is the correct structure of an atom?
Elements in the same column down belong to the same
Answer:
same what
Explanation:
what is the force that result because of each kind of combination called?
Answer:
a force is push or pull that act on object as a result of object interaction its surrounding.
Explanation: