Compare which element would have larger first ionization energy: an alkali metal in Period 2 or an alkali metal in Period 4?
AW: I think it would be alkali metal on period 2
Answer:
An alkali metal present in period 2 have larger first ionization energy.
Explanation:
Ionization energy:
The amount of energy required to remove the electron from the atom is called ionization energy.
Trend along period:
As we move from left to right across the periodic table the number of valance electrons in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction. The electrons are pull towards the nucleus and valance shell get closer to the nucleus. As a result of this greater nuclear attraction atomic radius decreases and ionization energy increases because it is very difficult to remove the electron from atom and more energy is required.
Trend along group:
As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased.
As the size of atom increases the ionization energy from top to bottom also decreases because it becomes easier to remove the electron because of less nuclear attraction and as more electrons are added the outer electrons becomes more shielded and away from nucleus. Thus alkali metal present in period 2 have larger ionization energy because of more nuclear attraction as compared to the alkali metal present in period 4.
Which best explains how photosynthesis is helpful to humans? It reduces the amount of harmful rays released by the sun. It increases the levels of carbon dioxide in the air. It provides oxygen for humans to breathe. It produces proteins, which humans can eat.
Answer:
it provides oxygen for the human to breathe
Explanation:
During photosynthesis plants absorbs carbon dioxide from the atmosphere and release oxygen into the air. Hence, it increases the level of oxygen for breath.
What is photosynthesis?Photosynthesis is a biological process by which green plants produce energy and molecular oxygen in leaf by the aid of light energy. The photoactive pigments chlorophyll in green leaves absorbs light energy sufficient for this process.
The photosynthetic reaction involves combination of carbon dioxide and water to form glucose and oxygen as written below:
[tex]\rm 6H_{2}O + 6CO_{2} \rightarrow C_{6}H_{12}O_{6} + 6O_{2}[/tex].
Therefore, photosynthesis decrease the level of carbon dioxide and increase the level of oxygen in the air . Thus, plant biomass helps us to provide oxygen to breath.
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What is the formula for Hydroxide
Answer:
OH-
Explanation:
it's consists of an oxygen and hydrogen atom held together by a covalent bond and carries a negative electric charge
How does a scientist test their hypothesis?
Answer:
Conducting experiments and using the scientific method.
Explanation:
Scientists (and other people) test hypotheses by conducting experiments. The purpose of an experiment is to determine whether observations of the real world agree with or conflict with the predictions derived from a hypothesis. If they agree, confidence in the hypothesis increases; otherwise, it decreases.
How many protons in an atom of beryllium
Answer: 4
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Please check my chem answers! Due in a few minutes!
Answer:
their correct
Explanation:
your answers are correct
An ice cream company decides to make a new lower calorie flavor,but testers reported that the flavor wasnt as good as the original.Is this an example of trade off
Answer:
Yes, the given instance is an example of a trade-off.
Explanation:
The trade-off seems to be a strategy to minimize or surrender one or more favorable results in consideration for increasing either receiving other favorable results to optimize cumulative benefit or efficacy within such conditions.The above is indeed a trade-off since the participants are experimenting in exchange again for ice cream individuals have to enjoy. The ice cream manufacturer always gets a review of the technician in exchange for free ice cream.which shows as evidence for a scientific claim. A- surveys of public opinion B- company advertisments C-controlled experiments D- personal websites
Answer:
A
You do not know if the advertisement is lying to you. Controlled experiments will be biased and personal websites will say what they think, not following the data & science.
If the density of a gold coin is 19.3g/cm3, what would be the density of the coin if you cut it in half?
Is this statement true or false? Why?
Chemical reactions are nothing more than rearrangements of protons.
Answer:
False. Answer in pic above
In fact protons have no role in chemical reactions. The regrouping of atoms itself forms the new products in chemical reactions. The reactions involves the loss/gain or sharing of electrons.
What is a chemical reaction ?A chemical reaction is a chemical change in which two or more atoms combine together to form a new product or a compound decomposes to form its constituent compounds. This involves breaking or making of bonds.
In a chemical reaction, no change occurs in the nuclear composition but the valence electrons are involved in the reaction. Atoms loss or gain electrons or share valence electrons with other atoms to form ne compounds.
The electrostatic force of attraction or the overlapping of atomic orbitals make the new products in a chemical reaction. Hence, the statement is false.
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Which of these would have lowest kinetic energy
Boiling water
Ice water
Refrigerated water
Water at room temperature
Answer:
The answer is ice water, since the particles of a solid have very low kinetic energy.
Explanation:
Answer:
Iced water.
Explanation:
It's a solid. Within a given substance, such as water, particles in the solid state have the least amount of kinetic energy.
As water freezes, it does so because after thermal energy leaves the particles, the average translational+rotational kinetic energy decreases, but the total average kinetic energy does not... and the temperature does not change either.
STATE TRUE OR FALSE
a) natural gas has a characteristic odour
b) natural gas is heavier than air
c) synthetic fibres, polymers, dyes are synthesized from petrochemicals
d) we should use convential bulb's instead if LED'S
e) emission of CO2 gas during burning of fossil fuels burn global warming
HELP ASAP!! A pebble is dropped into a graduated cylinder and the volume rises from 25.0 mL to 31.0 mL. The mass of the pebble is 2.9g. What is the density of the pebble? (g/mL)
Answer:
The density of the pebble is 0.483g/mL (rounded), but it's 0.48333333333333 without rounding. Hope this helped! :)
Explanation:
Volume= 6.0mL Density=Mass/Volume
Mass= 2.9g
D=2.9g/6.0mL
D=0.48333333333333g/mL
or
D≈0.483g/mL
The density of plutonium is 19.84 g/cm². What is its mass if the container has
volume of 250 cm?
Answer:
the answer is 7.936X 10⁻⁷kg.... the unit for volume must be cm³
Explanation:
we know,
ρ =m/v
given,
ρ =19.84/1000X(100)²= 1.984X10⁻⁶kg/m²
V (volume of the container means the volume of the element)=2.5 m³
NOW putting in the equation
1.984X10⁻⁶/2.5=m
or, m=7.936X 10⁻⁷kg(ANS)
thank u(i am not 100% sure but think it shoud be the answer)
Which statement best describes how the use of gasoline in a car relates to the discipline of chemistry?
The materials used come from the ground,
The gasoline undergoes a change as it burns
A car uses the gasoline to move
All parts of the car are composed of chemicals.
Answer:
The gasoline undergoes a change as it burns.
Explanation:
Just took the Unit Test review ((:
Answer:
b
Explanation:
because i said so brudda
how many bonds are broken in 2O2
Answer:
c5mvmifvidvj8dvj9r kf9,g
A scientist studies living organisms in their natural setting
Answer:
did not
Explanation:
ask
What is the SI unit for mass
Answer:
kilo gram
Explanation:
kilogram(kg)
Answer:
Kilogram (Kg).......
6.
Which best represents a particle containing 28 protons, 26 electrons, and 34 neutrons?
A Fe2-
B
54
2+
28N;
C%2Fe2-
DSNi2+
Answer:
Ni^2+
Explanation:
The following data were obtained from the question:
Proton = 28
Electron = 26
Neutron = 34
Next, we shall determine the atomic number of the element.
Atomic number of an element is simply defined as the number of protons in the atom of an element.
Thus,
Atomic number = proton number
Proton = 28
Atomic number = proton number = 28
Atomic number = 28
Therefore, the element is Nickel since no two elements have the same atomic number.
Finally, we shall determine the charge on the Nickel atom as follow:
Proton = 28
Electron = 26
Charge on atom =
Charge on atom = Proton – Electron
Charge on atom = 28 – 26
Charge on atom = +2
Therefore, we can represent the Particle as Ni^2+
Calculate the destiny of the object that has a mass of 453 g and occupies the volume of 225 cm3
A ( 2.01g/cm3
B( 5.00 g/cm3
C( 453 g/cm3
D( 228 g/cm3
density = 2.013g/cm3
Explanation:
density = mass/volume
density = 453g/225cm3
density = 2.013g/cm3
Members of group # ___ do not form ions or react with other elements.
Answer:
VIIA group donot form ions or react with other elements. This group is also called noble gases or inert gases which donot take part in chemical reaction.
Atoms contain positive, negative, and neutral. what happens when two positively charged particles are close together?
A.They repel each other
B.They cancel each other
C.They attract each other
D.They have no effect
Answer:
they repel each other
Explanation:
A is the ans
The compound M-O-H can act both as acid or base depending upon the ionisation
enthalpy of the element M. Justify by taking elements (M) of the third period of the
periodic table.
action
Answer:
Explanation:
A compound that can act both as an acid and a base is called an amphoteric substance. A good example (based on the question) of an amphoteric substance is the Aluminium hydroxide [Al(OH)₃] where Aluminium is the "M" in M-O-H. Aluminium is in the third period of the periodic table. The reaction below shows aluminium can act both as an acid and as a base in different neutralization reactions.
As an acid
Al(OH)₃ + 3NaOH ⇒ Na₃AlO₃ + 3H₂O
As a base
3HCl + Al(OH)₃ ⇒ AlCl₃ + 3H₂O
NOTE: A neutralization reaction is a reaction between an acid and a base to give you salt and water
Which of the following is a single replacement reaction?
( a. Ba(OH)2 + H2SO4 → BaSO4 + 2H2O
( b. 2Mg + O2 → 2MgO
(c. H2O+ CO2 → H2CO3
(d. Zn + H2SO4 → ZnSO4 + H2
Answer:
D.
Explanation:
A. is double replacement. Ex. AX + BY -> AY + BX
B. is synthesis Ex. A + B -> AB
C. is synthesis
D. is Single replacement -> A + BX -> Ax + B
- Study definitions and examples of these and that will help.
When zinc react with sulfuric acid, then zinc sulphate is formed. Zn + H₂SO₄ → ZnSO₄ + H₂ this reaction is replacement reaction.
What is replacement reaction ?One element in a molecule is replaced by another in a chemical reaction known as a single-displacement reaction, sometimes referred to as a single replacement reaction or exchange reaction.
One element in a compound is switched out for another in a single replacement reaction. In a double-replacement process, the anions or cations of two ionic compounds are switched. In a double-replacement reaction known as a precipitation, a solid precipitate is one of the products.
One ingredient replaces another comparable element in a compound in a single-replacement reaction.
Thus, option D is correct.
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Which of these is an example of an abiotic factor?
What are the choices? I'll answer once you tell me those
Answer:
sunlight is an abiotic factor
Explanation:
Need help with this
Answer:
C option is the correct answer
4. m stands for....
a) millimeter
C) centimeter
b) meter
d) Liter
Answer:
meter
Explanation:
which is the odd one out of clay pot , chalk , steel spoon and glass bowl(with explanation)
Answer:
chalk
Explanation:
most of them are utensils
Which of the following statement(s) are true about the atoms of any element?
a) The number of protons in an atom of an element is unique to each element.
b) The number of protons and neutrons in an atom of an element is unique to each element
c) A proton in an atom of one element is identical to a proton in an atom of another element.
d) The number of protons in an atom of an element is the same for all elements.
Answer:
C
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Which of the following statements concerning the sample size of an experiment is not accurate?
A. A smaller sample size decreases confidence in the accuracy of a study.
B. A larger sample increases confidence in the accuracy of a study.
C. A smaller sample size increases generalizability of a study
D. A larger sample increases generalizability of a study.
Answer:
It's actually C. A smaller sample size increases generalizability of a study
Explanation: