Question

Can someone help me with Chemistry A unit 3 Lesson 11? Please, ive been working on it for 2 days now

Answer 1

what? can you write the unit....i dont know what are you talking about

Answer 2

. Which of the following was NOT among Democritus's ideas? (1 point)Matter consists of tiny particles called atoms.
Atoms are indivisible.
Atoms retain their identity in a chemical reaction.
Atoms are indestructible.

2. Which of the following was originally a tenet of Dalton's atomic theory, but had to be revised about a century ago? (1 point)Atoms are tiny indivisible particles.
Atoms of the same element are identical.
Compounds are made by combining atoms.
Atoms of different elements can combine with one another in simple whole number ratios.

3. The comparison of the number of atoms in a copper coin the size of a penny with the number of people on Earth is made to illustrate which of the following? (1 point)that atoms are indivisible
that atoms are very small
that atoms are very large
that in a copper penny, there is one atom for every person on Earth

4. Which of the following is true about subatomic particles?
(1 point)Electrons are negatively charged and are the heaviest subatomic particle.
Protons are positively charged and the lightest subatomic particle.
Neutrons have no charge and are the lightest subatomic particle.
The mass of a neutron nearly equals the mass of a proton.

5. The nucleus of an atom is _____. (1 point)the central core and is composed of protons and neutrons
positively charged and has more protons than neutrons
negatively charged and has a high density
negatively charged and has a low density

6. An element has an atomic number of 76. The number of protons and electrons in a neutral atom of the element are ____. (1 point)152 protons and 76 electrons
76 protons and 0 electrons
38 protons and 38 electrons
76 protons and 76 electrons

7. Isotopes of the same element have different _____. (1 point)numbers of neutrons
numbers of protons
numbers of electrons
atomic numbers

8. The mass number of an element is equal to _____. (1 point)the total number of electrons in the nucleus
the total number of protons and neutrons in the nucleus
less than twice the atomic number
a constant number for the lighter elements

9. Which of the following isotopes has the same number of neutrons as phosphorus-31? (atomic number 15) (1 point)ChemA_Test_Q38a
ChemA_Test_Q38b
ChemA_Test_Q38c
ChemA_Test_Q38d

10. Which of the following equals one atomic mass unit? (1 point)the mass of one electron
the mass of one helium-4 atom
the mass of one carbon-12 atom
one-twelfth the mass of one carbon-12 atom

11. The atomic mass of an element depends upon the _____. (1 point)mass of each electron in that element
mass of each isotope of that element
relative abundance of protons in that element
mass and relative abundance of each isotope of that element

12. In the Bohr model of the atom, an electron in an orbit has a fixed _____. (1 point)position
color
energy
size

13. The principal quantum number indicates what property of an electron? (1 point)position
speed
energy level
electron cloud shape

14. When an electron moves from a lower to a higher energy level, the electron _____. (1 point)always doubles its energy
absorbs a continously variable amount of energy
absorbs a quantum of energy
moves closer to the nucleus

15. If three electrons are available to fill three empty 2p atomic orbitals, how will the electrons be distributed in the three orbitals? (1 point)one electron in each orbital
two electrons in one orbital, one in another, none in the third
three in one orbital, none in the other two
Three electrons cannot fill three empty 2p atomic orbitals.

16. Which electron configuration of the 4f energy sublevel is the most stable? (1 point)4f7
4f
4f13
4f14

17. The modern periodic table is arranged in order of increasing atomic _____. (1 point)mass
charge
number
radius

18. To what category of elements does an element belong if it is a poor conductor of electricity? (1 point)transition elements
metalloids
nonmetals
metals

19. Which of the following groupings contains only representative elements? (1 point)Cu, Co, Cd
Ni, Fe, Zn
Al, Mg, Li
Hg, Cr, Ag

20. Atomic size generally _____. (1 point)increases as you move from left to right across a period
decreases as you move from top to bottom within a group
remains constant within a period
decreases as you move from left to right across a period

21. Which of the following statements is true about ions? (1 point)Cations form when an atom gains electrons.
Cations form when an atom loses electrons.
Anions form when an atom gains protons.
Anions form when an atom loses protons.

22. Which is the element with the highest electronegativity value? (1 point)cesium
helium
calcium
fluorine

23. List the number of protons, neutrons, and electrons in ChemA_Test_Q45. (3 points)

24. A fictitious element X is composed of 10.0 percent of the isotope ChemA_Test_Q46a, 20.0 percent of the isotope ChemA_Test_Q46b, and 70.0 percent of the isotope ChemA_Test_Q46c. Estimate the atomic mass of element X. (3 points)

The atomic number of chlorine is 17.
25. Give the electron configuration for a neutral atom of chlorine. (3 points)

26. Explain why the 4s sublevel fills before the 3d sublevel begins to fill as electrons are added. (4 points)

27. Describe the trends in first ionization energy within groups and across periods in the periodic table. Provide Examples. (3 points)

Answer 3

This is it all but Ive been stuck for a while

Answer 4

1. 3
2. 1
3. 2
4. 4
5. 1
6. 4
7. 1
8. 2
9. (no choices given)
10. 3

Answer 5

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